diff --git a/byond-extools.dll b/byond-extools.dll
index 7c45514fe2..ec50515705 100644
Binary files a/byond-extools.dll and b/byond-extools.dll differ
diff --git a/code/__DEFINES/atmospherics.dm b/code/__DEFINES/atmospherics.dm
index c609bdd230..47b0b65967 100644
--- a/code/__DEFINES/atmospherics.dm
+++ b/code/__DEFINES/atmospherics.dm
@@ -281,12 +281,12 @@ GLOBAL_LIST_INIT(atmos_adjacent_savings, list(0,0))
 #define CALCULATE_ADJACENT_TURFS(T) SSadjacent_air.queue[T] = 1
 #endif
 
-GLOBAL_VAR(atmos_extools_initialized) // this must be an uninitialized (null) one or init_fastmos will be called twice because reasons
+GLOBAL_VAR(atmos_extools_initialized) // this must be an uninitialized (null) one or init_monstermos will be called twice because reasons
 #define ATMOS_EXTOOLS_CHECK if(!GLOB.atmos_extools_initialized){\
 	GLOB.atmos_extools_initialized=TRUE;\
 	var/extools = world.GetConfig("env", "EXTOOLS_DLL") || "./byond-extools.dll";\
 	if(fexists(extools)){\
-		var/result = call(extools,"init_fastmos")();\
+		var/result = call(extools,"init_monstermos")();\
 		if(result != "ok") {CRASH(result);}\
 	} else {\
 		CRASH("byond-extools.dll does not exist!");\
diff --git a/code/__DEFINES/subsystems.dm b/code/__DEFINES/subsystems.dm
index 3abef3a61c..4e0d636ae4 100644
--- a/code/__DEFINES/subsystems.dm
+++ b/code/__DEFINES/subsystems.dm
@@ -135,12 +135,13 @@
 // SSair run section
 #define SSAIR_PIPENETS 1
 #define SSAIR_ATMOSMACHINERY 2
-#define SSAIR_REACTQUEUE 3
-#define SSAIR_EXCITEDGROUPS 4
-#define SSAIR_HIGHPRESSURE 5
-#define SSAIR_HOTSPOTS 6
-#define SSAIR_SUPERCONDUCTIVITY 7
-#define SSAIR_REBUILD_PIPENETS 8
+#define SSAIR_EXCITEDGROUPS 3
+#define SSAIR_HIGHPRESSURE 4
+#define SSAIR_HOTSPOTS 5
+#define SSAIR_SUPERCONDUCTIVITY 6
+#define SSAIR_REBUILD_PIPENETS 7
+#define SSAIR_EQUALIZE 8
+#define SSAIR_ACTIVETURFS 9
 
 #define COMPILE_OVERLAYS(A)\
 	if (TRUE) {\
diff --git a/code/controllers/subsystem/air.dm b/code/controllers/subsystem/air.dm
index d8c7724333..21a919cc45 100644
--- a/code/controllers/subsystem/air.dm
+++ b/code/controllers/subsystem/air.dm
@@ -6,7 +6,7 @@ SUBSYSTEM_DEF(air)
 	flags = SS_BACKGROUND
 	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME
 
-	var/cost_turf_reactions = 0
+	var/cost_turfs = 0
 	var/cost_groups = 0
 	var/cost_highpressure = 0
 	var/cost_hotspots = 0
@@ -14,10 +14,9 @@ SUBSYSTEM_DEF(air)
 	var/cost_pipenets = 0
 	var/cost_rebuilds = 0
 	var/cost_atmos_machinery = 0
+	var/cost_equalize = 0
 
-	var/list/excited_groups = list()
 	var/list/active_turfs = list()
-	var/list/turf_react_queue = list()
 	var/list/hotspots = list()
 	var/list/networks = list()
 	var/list/pipenets_needing_rebuilt = list()
@@ -38,20 +37,21 @@ SUBSYSTEM_DEF(air)
 	var/map_loading = TRUE
 	var/list/queued_for_activation
 
+	var/log_explosive_decompression = TRUE // If things get spammy, admemes can turn this off.
+
 /datum/controller/subsystem/air/stat_entry(msg)
 	msg += "C:{"
-	msg += "RQ:[round(cost_turf_reactions,1)]|"
+	msg += "EQ:[round(cost_equalize,1)]|"
+	msg += "AT:[round(cost_turfs,1)]|"
 	msg += "EG:[round(cost_groups,1)]|"
 	msg += "HP:[round(cost_highpressure,1)]|"
 	msg += "HS:[round(cost_hotspots,1)]|"
 	msg += "SC:[round(cost_superconductivity,1)]|"
 	msg += "PN:[round(cost_pipenets,1)]|"
-	msg += "RB:[round(cost_rebuilds,1)]|"
 	msg += "AM:[round(cost_atmos_machinery,1)]"
 	msg += "} "
 	msg += "AT:[active_turfs.len]|"
-	msg += "RQ:[turf_react_queue.len]|"
-	msg += "EG:[excited_groups.len]|"
+	msg += "EG:[get_amt_excited_groups()]|"
 	msg += "HS:[hotspots.len]|"
 	msg += "PN:[networks.len]|"
 	msg += "HP:[high_pressure_delta.len]|"
@@ -59,8 +59,8 @@ SUBSYSTEM_DEF(air)
 	msg += "AT/MS:[round((cost ? active_turfs.len/cost : 0),0.1)]"
 	..(msg)
 
-
 /datum/controller/subsystem/air/Initialize(timeofday)
+	extools_update_ssair()
 	map_loading = FALSE
 	setup_allturfs()
 	setup_atmos_machinery()
@@ -68,6 +68,7 @@ SUBSYSTEM_DEF(air)
 	gas_reactions = init_gas_reactions()
 	return ..()
 
+/datum/controller/subsystem/air/proc/extools_update_ssair()
 
 /datum/controller/subsystem/air/fire(resumed = 0)
 	var/timer = TICK_USAGE_REAL
@@ -99,12 +100,21 @@ SUBSYSTEM_DEF(air)
 		if(state != SS_RUNNING)
 			return
 		resumed = 0
-		currentpart = SSAIR_REACTQUEUE
+		currentpart = SSAIR_ACTIVETURFS // set this to EQUALIZE for monstermos
 
-	if(currentpart == SSAIR_REACTQUEUE)
+	if(currentpart == SSAIR_EQUALIZE)
 		timer = TICK_USAGE_REAL
-		process_react_queue(resumed)
-		cost_turf_reactions = MC_AVERAGE(cost_turf_reactions, TICK_DELTA_TO_MS(TICK_USAGE_REAL - timer))
+		process_turf_equalize(resumed)
+		cost_equalize = MC_AVERAGE(cost_equalize, TICK_DELTA_TO_MS(TICK_USAGE_REAL - timer))
+		if(state != SS_RUNNING)
+			return
+		resumed = 0
+		currentpart = SSAIR_ACTIVETURFS
+
+	if(currentpart == SSAIR_ACTIVETURFS)
+		timer = TICK_USAGE_REAL
+		process_active_turfs(resumed)
+		cost_turfs = MC_AVERAGE(cost_turfs, TICK_DELTA_TO_MS(TICK_USAGE_REAL - timer))
 		if(state != SS_RUNNING)
 			return
 		resumed = 0
@@ -146,6 +156,8 @@ SUBSYSTEM_DEF(air)
 		resumed = 0
 	currentpart = SSAIR_REBUILD_PIPENETS
 
+
+
 /datum/controller/subsystem/air/proc/process_pipenets(resumed = 0)
 	if (!resumed)
 		src.currentrun = networks.Copy()
@@ -180,19 +192,6 @@ SUBSYSTEM_DEF(air)
 			return
 
 
-/datum/controller/subsystem/air/proc/process_react_queue(resumed = 0)
-	if(!resumed)
-		src.currentrun = turf_react_queue.Copy()
-	var/list/currentrun = src.currentrun
-	while(currentrun.len)
-		var/turf/open/T = currentrun[currentrun.len]
-		currentrun.len--
-		if(T)
-			T.process_cell_reaction()
-		if(MC_TICK_CHECK)
-			return
-
-
 /datum/controller/subsystem/air/proc/process_super_conductivity(resumed = 0)
 	if (!resumed)
 		src.currentrun = active_super_conductivity.Copy()
@@ -227,10 +226,45 @@ SUBSYSTEM_DEF(air)
 		high_pressure_delta.len--
 		T.high_pressure_movements()
 		T.pressure_difference = 0
+		T.pressure_specific_target = null
 		if(MC_TICK_CHECK)
 			return
 
+/datum/controller/subsystem/air/proc/process_turf_equalize(resumed = 0)
+	//cache for sanic speed
+	var/fire_count = times_fired
+	if (!resumed)
+		src.currentrun = active_turfs.Copy()
+	//cache for sanic speed (lists are references anyways)
+	var/list/currentrun = src.currentrun
+	while(currentrun.len)
+		var/turf/open/T = currentrun[currentrun.len]
+		currentrun.len--
+		if (T)
+			T.equalize_pressure_in_zone(fire_count)
+			//equalize_pressure_in_zone(T, fire_count)
+		if (MC_TICK_CHECK)
+			return
+
+/datum/controller/subsystem/air/proc/process_active_turfs(resumed = 0)
+	//cache for sanic speed
+	var/fire_count = times_fired
+	if (!resumed)
+		src.currentrun = active_turfs.Copy()
+	//cache for sanic speed (lists are references anyways)
+	var/list/currentrun = src.currentrun
+	while(currentrun.len)
+		var/turf/open/T = currentrun[currentrun.len]
+		currentrun.len--
+		if (T)
+			T.process_cell(fire_count)
+		if (MC_TICK_CHECK)
+			return
+
 /datum/controller/subsystem/air/proc/process_excited_groups(resumed = 0)
+	if(process_excited_groups_extools(resumed, (Master.current_ticklimit - TICK_USAGE) * 0.01 * world.tick_lag))
+		sleep()
+	/*
 	if (!resumed)
 		src.currentrun = excited_groups.Copy()
 	//cache for sanic speed (lists are references anyways)
@@ -246,29 +280,33 @@ SUBSYSTEM_DEF(air)
 			EG.dismantle()
 		if (MC_TICK_CHECK)
 			return
+	*/
+
+/datum/controller/subsystem/air/proc/process_excited_groups_extools()
+/datum/controller/subsystem/air/proc/get_amt_excited_groups()
 
 /datum/controller/subsystem/air/proc/remove_from_active(turf/open/T)
 	active_turfs -= T
-	SSair_turfs.currentrun -= T
+	if(currentpart == SSAIR_ACTIVETURFS)
+		currentrun -= T
 	#ifdef VISUALIZE_ACTIVE_TURFS
 	T.remove_atom_colour(TEMPORARY_COLOUR_PRIORITY, "#00ff00")
 	#endif
 	if(istype(T))
-		T.excited = 0
-		if(T.excited_group)
-			T.excited_group.garbage_collect()
-	remove_from_react_queue(T)
+		T.set_excited(FALSE)
+		T.eg_garbage_collect()
 
 /datum/controller/subsystem/air/proc/add_to_active(turf/open/T, blockchanges = 1)
 	if(istype(T) && T.air)
 		#ifdef VISUALIZE_ACTIVE_TURFS
 		T.add_atom_colour("#00ff00", TEMPORARY_COLOUR_PRIORITY)
 		#endif
-		T.excited = TRUE
-		active_turfs[T] = SSair_turfs.currentrun[T] = TRUE
-		if(blockchanges && T.excited_group)
-			T.excited_group.garbage_collect()
-		add_to_react_queue(T)
+		T.set_excited(TRUE)
+		active_turfs |= T
+		if(currentpart == SSAIR_ACTIVETURFS)
+			currentrun |= T
+		if(blockchanges)
+			T.eg_garbage_collect()
 	else if(T.flags_1 & INITIALIZED_1)
 		for(var/turf/S in T.atmos_adjacent_turfs)
 			add_to_active(S)
@@ -279,17 +317,6 @@ SUBSYSTEM_DEF(air)
 	else
 		T.requires_activation = TRUE
 
-/datum/controller/subsystem/air/proc/add_to_react_queue(turf/open/T)
-	if(istype(T) && T.air)
-		turf_react_queue[T] = TRUE
-		if(currentpart == SSAIR_REACTQUEUE)
-			currentrun[T] = TRUE
-
-/datum/controller/subsystem/air/proc/remove_from_react_queue(turf/open/T)
-	turf_react_queue -= T
-	if(currentpart == SSAIR_REACTQUEUE)
-		currentrun -= T
-
 /datum/controller/subsystem/air/StartLoadingMap()
 	LAZYINITLIST(queued_for_activation)
 	map_loading = TRUE
@@ -337,11 +364,11 @@ SUBSYSTEM_DEF(air)
 
 		while (turfs_to_check.len)
 		var/ending_ats = active_turfs.len
-		for(var/thing in excited_groups)
+		/*for(var/thing in excited_groups)
 			var/datum/excited_group/EG = thing
-			EG.self_breakdown(space_is_all_consuming = 1)
-			EG.dismantle()
-			CHECK_TICK
+			//EG.self_breakdown(space_is_all_consuming = 1)
+			//EG.dismantle()
+			CHECK_TICK*/
 
 		var/msg = "HEY! LISTEN! [DisplayTimeText(world.timeofday - timer)] were wasted processing [starting_ats] turf(s) (connected to [ending_ats] other turfs) with atmos differences at round start."
 		to_chat(world, "<span class='boldannounce'>[msg]</span>")
@@ -349,6 +376,7 @@ SUBSYSTEM_DEF(air)
 
 /turf/open/proc/resolve_active_graph()
 	. = list()
+	/*
 	var/datum/excited_group/EG = excited_group
 	if (blocks_air || !air)
 		return
@@ -369,7 +397,8 @@ SUBSYSTEM_DEF(air)
 			EG.add_turf(ET)
 		if (!ET.excited)
 			ET.excited = 1
-			. += ET
+			. += ET*/
+
 /turf/open/space/resolve_active_graph()
 	return list()
 
@@ -387,9 +416,8 @@ SUBSYSTEM_DEF(air)
 		CHECK_TICK
 
 /datum/controller/subsystem/air/proc/setup_template_machinery(list/atmos_machines)
-	if(!initialized)
-		return
-
+	if(!initialized) // yogs - fixes randomized bars
+		return // yogs
 	for(var/A in atmos_machines)
 		var/obj/machinery/atmospherics/AM = A
 		AM.atmosinit()
@@ -413,6 +441,7 @@ SUBSYSTEM_DEF(air)
 
 #undef SSAIR_PIPENETS
 #undef SSAIR_ATMOSMACHINERY
+#undef SSAIR_ACTIVETURFS
 #undef SSAIR_EXCITEDGROUPS
 #undef SSAIR_HIGHPRESSURE
 #undef SSAIR_HOTSPOTS
diff --git a/code/controllers/subsystem/air_turfs.dm b/code/controllers/subsystem/air_turfs.dm
index 9dd41aede5..7320defcae 100644
--- a/code/controllers/subsystem/air_turfs.dm
+++ b/code/controllers/subsystem/air_turfs.dm
@@ -1,5 +1,5 @@
 //WHAT IF WE TAKE THE ACTIVE TURF PROCESSING AND PUSH IT SOMEWHERE ELSE!!!
-
+/*
 SUBSYSTEM_DEF(air_turfs)
 	name = "Atmospherics - Turfs"
 	init_order = INIT_ORDER_AIR_TURFS
@@ -24,3 +24,4 @@ SUBSYSTEM_DEF(air_turfs)
 			return
 	resumed = 0
 	return
+*/
diff --git a/code/game/machinery/doors/airlock.dm b/code/game/machinery/doors/airlock.dm
index 3bc8aff809..5665edfba2 100644
--- a/code/game/machinery/doors/airlock.dm
+++ b/code/game/machinery/doors/airlock.dm
@@ -93,7 +93,7 @@
 	var/shuttledocked = 0
 	var/delayed_close_requested = FALSE // TRUE means the door will automatically close the next time it's opened.
 
-	var/air_tight = FALSE	//TRUE means density will be set as soon as the door begins to close
+	air_tight = FALSE
 	var/prying_so_hard = FALSE
 
 	rad_flags = RAD_PROTECT_CONTENTS | RAD_NO_CONTAMINATE
diff --git a/code/game/machinery/doors/door.dm b/code/game/machinery/doors/door.dm
index c4c712ca25..5934658ba3 100644
--- a/code/game/machinery/doors/door.dm
+++ b/code/game/machinery/doors/door.dm
@@ -16,6 +16,7 @@
 	interaction_flags_atom = INTERACT_ATOM_UI_INTERACT
 
 	var/secondsElectrified = 0
+	var/air_tight = FALSE	//TRUE means density will be set as soon as the door begins to close
 	var/shockedby
 	var/visible = TRUE
 	var/operating = FALSE
@@ -160,7 +161,7 @@
 			open()
 		else
 			close()
-		return
+		return TRUE
 	if(density)
 		do_animate("deny")
 
@@ -180,11 +181,36 @@
 /obj/machinery/door/proc/try_to_crowbar(obj/item/I, mob/user)
 	return
 
+/obj/machinery/door/proc/is_holding_pressure()
+	var/turf/open/T = loc
+	if(!T)
+		return FALSE
+	if(!density)
+		return FALSE
+	// alrighty now we check for how much pressure we're holding back
+	var/min_moles = T.air.total_moles()
+	var/max_moles = min_moles
+	// okay this is a bit hacky. First, we set density to 0 and recalculate our adjacent turfs
+	density = FALSE
+	T.ImmediateCalculateAdjacentTurfs()
+	// then we use those adjacent turfs to figure out what the difference between the lowest and highest pressures we'd be holding is
+	for(var/turf/open/T2 in T.atmos_adjacent_turfs)
+		if((flags_1 & ON_BORDER_1) && get_dir(src, T2) != dir)
+			continue
+		var/moles = T2.air.total_moles()
+		if(moles < min_moles)
+			min_moles = moles
+		if(moles > max_moles)
+			max_moles = moles
+	density = TRUE
+	T.ImmediateCalculateAdjacentTurfs() // alright lets put it back
+	return max_moles - min_moles > 20
+
 /obj/machinery/door/attackby(obj/item/I, mob/user, params)
-	if(user.a_intent != INTENT_HARM && (istype(I, /obj/item/crowbar) || istype(I, /obj/item/twohanded/fireaxe)))
+	if(user.a_intent != INTENT_HARM && (I.tool_behaviour == TOOL_CROWBAR || istype(I, /obj/item/twohanded/fireaxe)))
 		try_to_crowbar(I, user)
 		return 1
-	else if(istype(I, /obj/item/weldingtool))
+	else if(I.tool_behaviour == TOOL_WELDER)
 		try_to_weld(I, user)
 		return 1
 	else if(!(I.item_flags & NOBLUDGEON) && user.a_intent != INTENT_HARM)
@@ -292,6 +318,8 @@
 	layer = closingLayer
 	if(!safe)
 		crush()
+	if(air_tight)
+		density = TRUE
 	sleep(5)
 	density = TRUE
 	sleep(5)
diff --git a/code/game/machinery/doors/firedoor.dm b/code/game/machinery/doors/firedoor.dm
index 28b9796bb6..eed6f2a040 100644
--- a/code/game/machinery/doors/firedoor.dm
+++ b/code/game/machinery/doors/firedoor.dm
@@ -23,6 +23,7 @@
 	assemblytype = /obj/structure/firelock_frame
 	armor = list("melee" = 30, "bullet" = 30, "laser" = 20, "energy" = 20, "bomb" = 10, "bio" = 100, "rad" = 100, "fire" = 95, "acid" = 70)
 	interaction_flags_machine = INTERACT_MACHINE_WIRES_IF_OPEN | INTERACT_MACHINE_ALLOW_SILICON | INTERACT_MACHINE_OPEN_SILICON | INTERACT_MACHINE_REQUIRES_SILICON | INTERACT_MACHINE_OPEN
+	var/emergency_close_timer = 0
 	var/nextstate = null
 	var/boltslocked = TRUE
 	var/list/affecting_areas
@@ -100,7 +101,7 @@
 		return
 
 	if(welded)
-		if(istype(C, /obj/item/wrench))
+		if(C.tool_behaviour == TOOL_WRENCH)
 			if(boltslocked)
 				to_chat(user, "<span class='notice'>There are screws locking the bolts in place!</span>")
 				return
@@ -114,7 +115,7 @@
 								 "<span class='notice'>You undo [src]'s floor bolts.</span>")
 			deconstruct(TRUE)
 			return
-		if(istype(C, /obj/item/screwdriver))
+		if(C.tool_behaviour == TOOL_SCREWDRIVER)
 			user.visible_message("<span class='notice'>[user] [boltslocked ? "unlocks" : "locks"] [src]'s bolts.</span>", \
 								 "<span class='notice'>You [boltslocked ? "unlock" : "lock"] [src]'s floor bolts.</span>")
 			C.play_tool_sound(src)
@@ -140,6 +141,17 @@
 		return
 
 	if(density)
+		if(is_holding_pressure())
+			// tell the user that this is a bad idea, and have a do_after as well
+			to_chat(user, "<span class='warning'>As you begin crowbarring \the [src] a gush of air blows in your face... maybe you should reconsider?</span>")
+			if(!do_after(user, 15, TRUE, src)) // give them a few seconds to reconsider their decision.
+				return
+			log_game("[key_name_admin(user)] has opened a firelock with a pressure difference at [AREACOORD(loc)]") // there bibby I made it logged just for you. Enjoy.
+			// since we have high-pressure-ness, close all other firedoors on the tile
+			whack_a_mole()
+		if(welded || operating || !density)
+			return // in case things changed during our do_after
+		emergency_close_timer = world.time + 60 // prevent it from instaclosing again if in space
 		open()
 	else
 		close()
@@ -194,6 +206,61 @@
 	. = ..()
 	latetoggle()
 
+/obj/machinery/door/firedoor/proc/whack_a_mole(reconsider_immediately = FALSE)
+	set waitfor = 0
+	for(var/cdir in GLOB.cardinals)
+		if((flags_1 & ON_BORDER_1) && cdir != dir)
+			continue
+		whack_a_mole_part(get_step(src, cdir), reconsider_immediately)
+	if(flags_1 & ON_BORDER_1)
+		whack_a_mole_part(get_turf(src), reconsider_immediately)
+
+/obj/machinery/door/firedoor/proc/whack_a_mole_part(turf/start_point, reconsider_immediately)
+	set waitfor = 0
+	var/list/doors_to_close = list()
+	var/list/turfs = list()
+	turfs[start_point] = 1
+	for(var/i = 1; (i <= turfs.len && i <= 11); i++) // check up to 11 turfs.
+		var/turf/open/T = turfs[i]
+		if(istype(T, /turf/open/space))
+			return -1
+		for(var/T2 in T.atmos_adjacent_turfs)
+			if(turfs[T2])
+				continue
+			var/is_cut_by_unopen_door = FALSE
+			for(var/obj/machinery/door/firedoor/FD in T2)
+				if((FD.flags_1 & ON_BORDER_1) && get_dir(T2, T) != FD.dir)
+					continue
+				if(FD.operating || FD == src || FD.welded || FD.density)
+					continue
+				doors_to_close += FD
+				is_cut_by_unopen_door = TRUE
+
+			for(var/obj/machinery/door/firedoor/FD in T)
+				if((FD.flags_1 & ON_BORDER_1) && get_dir(T, T2) != FD.dir)
+					continue
+				if(FD.operating || FD == src || FD.welded || FD.density)
+					continue
+				doors_to_close += FD
+				is_cut_by_unopen_door= TRUE
+			if(!is_cut_by_unopen_door)
+				turfs[T2] = 1
+	if(turfs.len > 10)
+		return // too big, don't bother
+	for(var/obj/machinery/door/firedoor/FD in doors_to_close)
+		FD.emergency_pressure_stop(FALSE)
+		if(reconsider_immediately)
+			var/turf/open/T = FD.loc
+			if(istype(T))
+				T.ImmediateCalculateAdjacentTurfs()
+
+/obj/machinery/door/firedoor/proc/emergency_pressure_stop(consider_timer = TRUE)
+	set waitfor = 0
+	if(density || operating || welded)
+		return
+	if(world.time >= emergency_close_timer || !consider_timer)
+		close()
+
 /obj/machinery/door/firedoor/deconstruct(disassembled = TRUE)
 	if(!(flags_1 & NODECONSTRUCT_1))
 		var/obj/structure/firelock_frame/F = new assemblytype(get_turf(src))
@@ -227,6 +294,30 @@
 	opacity = TRUE
 	density = TRUE
 
+/obj/machinery/door/firedoor/border_only/close()
+	if(density)
+		return TRUE
+	if(operating || welded)
+		return
+	var/turf/T1 = get_turf(src)
+	var/turf/T2 = get_step(T1, dir)
+	for(var/mob/living/M in T1)
+		if(M.stat == CONSCIOUS && M.pulling && M.pulling.loc == T2 && !M.pulling.anchored && M.pulling.move_resist <= M.move_force)
+			var/mob/living/M2 = M.pulling
+			if(!istype(M2) || !M2.buckled || !M2.buckled.buckle_prevents_pull)
+				to_chat(M, "<span class='notice'>You pull [M.pulling] through [src] right as it closes</span>")
+				M.pulling.forceMove(T1)
+				M.start_pulling(M2)
+				
+	for(var/mob/living/M in T2)
+		if(M.stat == CONSCIOUS && M.pulling && M.pulling.loc == T1 && !M.pulling.anchored && M.pulling.move_resist <= M.move_force)
+			var/mob/living/M2 = M.pulling
+			if(!istype(M2) || !M2.buckled || !M2.buckled.buckle_prevents_pull)
+				to_chat(M, "<span class='notice'>You pull [M.pulling] through [src] right as it closes</span>")
+				M.pulling.forceMove(T2)
+				M.start_pulling(M2)
+	. = ..()
+
 /obj/machinery/door/firedoor/border_only/CanPass(atom/movable/mover, turf/target)
 	if(istype(mover) && (mover.pass_flags & PASSGLASS))
 		return TRUE
@@ -293,7 +384,7 @@
 /obj/structure/firelock_frame/attackby(obj/item/C, mob/user)
 	switch(constructionStep)
 		if(CONSTRUCTION_PANEL_OPEN)
-			if(istype(C, /obj/item/crowbar))
+			if(C.tool_behaviour == TOOL_CROWBAR)
 				C.play_tool_sound(src)
 				user.visible_message("<span class='notice'>[user] starts prying something out from [src]...</span>", \
 									 "<span class='notice'>You begin prying out the wire cover...</span>")
@@ -307,7 +398,7 @@
 				constructionStep = CONSTRUCTION_WIRES_EXPOSED
 				update_icon()
 				return
-			if(istype(C, /obj/item/wrench))
+			if(C.tool_behaviour == TOOL_WRENCH)
 				if(locate(/obj/machinery/door/firedoor) in get_turf(src))
 					to_chat(user, "<span class='warning'>There's already a firelock there.</span>")
 					return
@@ -349,7 +440,7 @@
 				return
 
 		if(CONSTRUCTION_WIRES_EXPOSED)
-			if(istype(C, /obj/item/wirecutters))
+			if(C.tool_behaviour == TOOL_WIRECUTTER)
 				C.play_tool_sound(src)
 				user.visible_message("<span class='notice'>[user] starts cutting the wires from [src]...</span>", \
 									 "<span class='notice'>You begin removing [src]'s wires...</span>")
@@ -363,7 +454,7 @@
 				constructionStep = CONSTRUCTION_GUTTED
 				update_icon()
 				return
-			if(istype(C, /obj/item/crowbar))
+			if(C.tool_behaviour == TOOL_CROWBAR)
 				C.play_tool_sound(src)
 				user.visible_message("<span class='notice'>[user] starts prying a metal plate into [src]...</span>", \
 									 "<span class='notice'>You begin prying the cover plate back onto [src]...</span>")
@@ -378,7 +469,7 @@
 				update_icon()
 				return
 		if(CONSTRUCTION_GUTTED)
-			if(istype(C, /obj/item/crowbar))
+			if(C.tool_behaviour == TOOL_CROWBAR)
 				user.visible_message("<span class='notice'>[user] begins removing the circuit board from [src]...</span>", \
 									 "<span class='notice'>You begin prying out the circuit board from [src]...</span>")
 				if(!C.use_tool(src, user, 50, volume=50))
@@ -400,7 +491,7 @@
 									 "<span class='notice'>You begin adding wires to [src]...</span>")
 				playsound(get_turf(src), 'sound/items/deconstruct.ogg', 50, 1)
 				if(do_after(user, 60, target = src))
-					if(constructionStep != CONSTRUCTION_GUTTED || !B.use_tool(src, user, 0, 5))
+					if(constructionStep != CONSTRUCTION_GUTTED || B.get_amount() < 5 || !B)
 						return
 					user.visible_message("<span class='notice'>[user] adds wires to [src].</span>", \
 										 "<span class='notice'>You wire [src].</span>")
@@ -409,7 +500,7 @@
 					update_icon()
 				return
 		if(CONSTRUCTION_NOCIRCUIT)
-			if(istype(C, /obj/item/weldingtool))
+			if(C.tool_behaviour == TOOL_WELDER)
 				if(!C.tool_start_check(user, amount=1))
 					return
 				user.visible_message("<span class='notice'>[user] begins cutting apart [src]'s frame...</span>", \
diff --git a/code/game/objects/effects/temporary_visuals/miscellaneous.dm b/code/game/objects/effects/temporary_visuals/miscellaneous.dm
index 53adc46239..396f463136 100644
--- a/code/game/objects/effects/temporary_visuals/miscellaneous.dm
+++ b/code/game/objects/effects/temporary_visuals/miscellaneous.dm
@@ -486,4 +486,15 @@
 		addtimer(CALLBACK(src, .proc/end), 15)
 
 /obj/effect/constructing_effect/proc/end()
-	qdel(src)
\ No newline at end of file
+	qdel(src)
+
+/obj/effect/temp_visual/dir_setting/space_wind
+	icon = 'icons/effects/atmospherics.dmi'
+	icon_state = "space_wind"
+	layer = FLY_LAYER
+	duration = 20
+	mouse_opacity = 0
+
+/obj/effect/temp_visual/dir_setting/space_wind/Initialize(mapload, set_dir, set_alpha = 255)
+	. = ..()
+	alpha = set_alpha
diff --git a/code/game/objects/structures/holosign.dm b/code/game/objects/structures/holosign.dm
index 7ac3aba246..c49159a992 100644
--- a/code/game/objects/structures/holosign.dm
+++ b/code/game/objects/structures/holosign.dm
@@ -94,7 +94,7 @@
 	alpha = 150
 	resistance_flags = FIRE_PROOF
 
-/obj/structure/holosign/barrier/firelock/blocksTemperature()
+/obj/structure/holosign/barrier/firelock/BlockSuperconductivity()
 	return TRUE
 
 /obj/structure/holosign/barrier/combifan
@@ -110,7 +110,7 @@
 	CanAtmosPass = ATMOS_PASS_NO
 	resistance_flags = FIRE_PROOF
 
-/obj/structure/holosign/barrier/combifan/blocksTemperature()
+/obj/structure/holosign/barrier/combifan/BlockSuperconductivity()
 	return TRUE
 
 /obj/structure/holosign/barrier/combifan/Initialize()
diff --git a/code/game/turfs/change_turf.dm b/code/game/turfs/change_turf.dm
index 80e542dad8..3f1a681246 100644
--- a/code/game/turfs/change_turf.dm
+++ b/code/game/turfs/change_turf.dm
@@ -142,6 +142,7 @@ GLOBAL_LIST_INIT(blacklisted_automated_baseturfs, typecacheof(list(
 		. = ..()
 		if (!.) // changeturf failed or didn't do anything
 			QDEL_NULL(stashed_air)
+			update_air_ref()
 			return
 		var/turf/open/newTurf = .
 		newTurf.air.copy_from(stashed_air)
diff --git a/code/game/turfs/closed.dm b/code/game/turfs/closed.dm
index 99c7ed8231..0c2fd98aba 100644
--- a/code/game/turfs/closed.dm
+++ b/code/game/turfs/closed.dm
@@ -6,9 +6,14 @@
 	rad_flags = RAD_PROTECT_CONTENTS | RAD_NO_CONTAMINATE
 	rad_insulation = RAD_MEDIUM_INSULATION
 
+/turf/closed/Initialize()
+	. = ..()
+	update_air_ref()
+
 /turf/closed/AfterChange()
 	. = ..()
 	SSair.high_pressure_delta -= src
+	update_air_ref()
 
 /turf/closed/get_smooth_underlay_icon(mutable_appearance/underlay_appearance, turf/asking_turf, adjacency_dir)
 	return FALSE
diff --git a/code/game/turfs/open.dm b/code/game/turfs/open.dm
index 6a17b02d66..6552e29246 100644
--- a/code/game/turfs/open.dm
+++ b/code/game/turfs/open.dm
@@ -199,7 +199,7 @@
 			flash_color(L, flash_color = "#C80000", flash_time = 10)
 
 /turf/open/Initalize_Atmos(times_fired)
-	excited = 0
+	set_excited(FALSE)
 	update_visuals()
 
 	current_cycle = times_fired
@@ -207,9 +207,9 @@
 	for(var/i in atmos_adjacent_turfs)
 		var/turf/open/enemy_tile = i
 		var/datum/gas_mixture/enemy_air = enemy_tile.return_air()
-		if(!excited && air.compare(enemy_air))
+		if(!get_excited() && air.compare(enemy_air))
 			//testing("Active turf found. Return value of compare(): [is_active]")
-			excited = TRUE
+			set_excited(TRUE)
 			SSair.active_turfs |= src
 
 /turf/open/proc/GetHeatCapacity()
diff --git a/code/game/turfs/space/space.dm b/code/game/turfs/space/space.dm
index 26daa32107..b131a1ed70 100644
--- a/code/game/turfs/space/space.dm
+++ b/code/game/turfs/space/space.dm
@@ -27,6 +27,7 @@
 /turf/open/space/Initialize()
 	icon_state = SPACE_ICON_STATE
 	air = space_gas
+	update_air_ref()
 	vis_contents.Cut() //removes inherited overlays
 	visibilityChanged()
 
diff --git a/code/game/world.dm b/code/game/world.dm
index 10431e4af9..7f6b2c5da7 100644
--- a/code/game/world.dm
+++ b/code/game/world.dm
@@ -262,6 +262,15 @@ GLOBAL_LIST(topic_status_cache)
 	shutdown_logging() // Past this point, no logging procs can be used, at risk of data loss.
 	..()
 
+/world/Del()
+	// memory leaks bad
+	var/num_deleted = 0
+	for(var/datum/gas_mixture/GM)
+		GM.__gasmixture_unregister()
+		num_deleted++
+	log_world("Deallocated [num_deleted] gas mixtures")
+	..()
+
 /world/proc/update_status()
 
 	var/list/features = list()
@@ -330,3 +339,6 @@ GLOBAL_LIST(topic_status_cache)
 	maxz++
 	SSmobs.MaxZChanged()
 	SSidlenpcpool.MaxZChanged()
+	world.refresh_atmos_grid()
+
+/world/proc/refresh_atmos_grid()
diff --git a/code/modules/atmospherics/environmental/LINDA_fire.dm b/code/modules/atmospherics/environmental/LINDA_fire.dm
index 40b91ed74c..81e103fba2 100644
--- a/code/modules/atmospherics/environmental/LINDA_fire.dm
+++ b/code/modules/atmospherics/environmental/LINDA_fire.dm
@@ -9,46 +9,31 @@
 	return
 
 
-/turf/open/hotspot_expose(exposed_temperature, exposed_volume, soh = FALSE, holo = FALSE)
-	var/datum/gas_mixture/air_contents = return_air()
-	if(!air_contents)
-		return 0
+/turf/open/hotspot_expose(exposed_temperature, exposed_volume, soh)
+	if(!air)
+		return
 
-	var/oxy = air_contents.get_moles(/datum/gas/oxygen)
-	var/tox = air_contents.get_moles(/datum/gas/plasma)
-	var/trit = air_contents.get_moles(/datum/gas/tritium)
+	var/oxy = air.get_moles(/datum/gas/oxygen)
+	if (oxy < 0.5)
+		return
+	var/tox = air.get_moles(/datum/gas/plasma)
+	var/trit = air.get_moles(/datum/gas/tritium)
 	if(active_hotspot)
 		if(soh)
-			if((tox > 0.5 || trit > 0.5) && oxy > 0.5)
-				if(active_hotspot.temperature < exposed_temperature*50)
-					active_hotspot.temperature = exposed_temperature*50
+			if(tox > 0.5 || trit > 0.5)
+				if(active_hotspot.temperature < exposed_temperature)
+					active_hotspot.temperature = exposed_temperature
 				if(active_hotspot.volume < exposed_volume)
 					active_hotspot.volume = exposed_volume
-		return 1
-
-	var/igniting = 0
+		return
 
 	if((exposed_temperature > PLASMA_MINIMUM_BURN_TEMPERATURE) && (tox > 0.5 || trit > 0.5))
-		igniting = 1
 
-	if(igniting)
-		if(oxy < 0.5)
-			return 0
-
-		active_hotspot = new /obj/effect/hotspot(src, holo)
-		active_hotspot.temperature = exposed_temperature*50
-		active_hotspot.volume = exposed_volume*25
+		active_hotspot = new /obj/effect/hotspot(src, exposed_volume*25, exposed_temperature)
 
 		active_hotspot.just_spawned = (current_cycle < SSair.times_fired)
 			//remove just_spawned protection if no longer processing this cell
 		SSair.add_to_active(src, 0)
-	else
-		var/datum/gas_mixture/heating = air_contents.remove_ratio(exposed_volume/air_contents.return_volume())
-		heating.set_temperature(exposed_temperature)
-		heating.react()
-		assume_air(heating)
-		air_update_turf()
-	return igniting
 
 //This is the icon for fire on turfs, also helps for nurturing small fires until they are full tile
 /obj/effect/hotspot
@@ -67,11 +52,13 @@
 	var/bypassing = FALSE
 	var/visual_update_tick = 0
 
-/obj/effect/hotspot/Initialize(mapload, holo = FALSE)
+/obj/effect/hotspot/Initialize(mapload, starting_volume, starting_temperature)
 	. = ..()
-	if(holo)
-		flags_1 |= HOLOGRAM_1
 	SSair.hotspots += src
+	if(!isnull(starting_volume))
+		volume = starting_volume
+	if(!isnull(starting_temperature))
+		temperature = starting_temperature
 	perform_exposure()
 	setDir(pick(GLOB.cardinals))
 	air_update_turf()
@@ -83,22 +70,19 @@
 
 	location.active_hotspot = src
 
-	if(volume > CELL_VOLUME*0.95)
-		bypassing = TRUE
-	else
-		bypassing = FALSE
+	bypassing = !just_spawned && (volume > CELL_VOLUME*0.95)
 
 	if(bypassing)
-		if(!just_spawned)
-			volume = location.air.reaction_results["fire"]*FIRE_GROWTH_RATE
-			temperature = location.air.return_temperature()
+		volume = location.air.reaction_results["fire"]*FIRE_GROWTH_RATE
+		temperature = location.air.return_temperature()
 	else
 		var/datum/gas_mixture/affected = location.air.remove_ratio(volume/location.air.return_volume())
-		affected.set_temperature(temperature)
-		affected.react(src)
-		temperature = affected.return_temperature()
-		volume = affected.reaction_results["fire"]*FIRE_GROWTH_RATE
-		location.assume_air(affected)
+		if(affected) //in case volume is 0
+			affected.set_temperature(temperature)
+			affected.react(src)
+			temperature = affected.return_temperature()
+			volume = affected.reaction_results["fire"]*FIRE_GROWTH_RATE
+			location.assume_air(affected)
 
 	for(var/A in location)
 		var/atom/AT = A
@@ -175,8 +159,7 @@
 		qdel(src)
 		return
 
-	if(location.excited_group)
-		location.excited_group.reset_cooldowns()
+	location.eg_reset_cooldowns()
 
 	if((temperature < FIRE_MINIMUM_TEMPERATURE_TO_EXIST) || (volume <= 1))
 		qdel(src)
@@ -185,12 +168,17 @@
 		qdel(src)
 		return
 
+	//Not enough to burn
+	// god damn it previous coder you made the INSUFFICIENT macro for a fucking reason why didn't you use it here smh
+	if((INSUFFICIENT(/datum/gas/plasma) && INSUFFICIENT(/datum/gas/tritium)) || INSUFFICIENT(/datum/gas/oxygen))
+		qdel(src)
+		return
+
 	perform_exposure()
 
 	if(bypassing)
 		icon_state = "3"
-		if(!(flags_1 & HOLOGRAM_1))
-			location.burn_tile()
+		location.burn_tile()
 
 		//Possible spread due to radiated heat
 		if(location.air.return_temperature() > FIRE_MINIMUM_TEMPERATURE_TO_SPREAD)
@@ -198,7 +186,7 @@
 			for(var/t in location.atmos_adjacent_turfs)
 				var/turf/open/T = t
 				if(!T.active_hotspot)
-					T.hotspot_expose(radiated_temperature, CELL_VOLUME/4, flags_1 & HOLOGRAM_1)
+					T.hotspot_expose(radiated_temperature, CELL_VOLUME/4)
 
 	else
 		if(volume > CELL_VOLUME*0.4)
@@ -222,14 +210,13 @@
 	var/turf/open/T = loc
 	if(istype(T) && T.active_hotspot == src)
 		T.active_hotspot = null
-	if(!(flags_1 & HOLOGRAM_1))
-		DestroyTurf()
+	DestroyTurf()
 	return ..()
 
 /obj/effect/hotspot/proc/DestroyTurf()
 	if(isturf(loc))
 		var/turf/T = loc
-		if(T.to_be_destroyed)
+		if(T.to_be_destroyed && !T.changing_turf)
 			var/chance_of_deletion
 			if (T.heat_capacity) //beware of division by zero
 				chance_of_deletion = T.max_fire_temperature_sustained / T.heat_capacity * 8 //there is no problem with prob(23456), min() was redundant --rastaf0
diff --git a/code/modules/atmospherics/environmental/LINDA_system.dm b/code/modules/atmospherics/environmental/LINDA_system.dm
index 760e4e22da..21dc6069a6 100644
--- a/code/modules/atmospherics/environmental/LINDA_system.dm
+++ b/code/modules/atmospherics/environmental/LINDA_system.dm
@@ -44,25 +44,32 @@
 	return FALSE
 
 /turf/proc/ImmediateCalculateAdjacentTurfs()
-	var/canpass = CANATMOSPASS(src, src)
+	var/canpass = CANATMOSPASS(src, src) 
 	var/canvpass = CANVERTICALATMOSPASS(src, src)
 	for(var/direction in GLOB.cardinals_multiz)
 		var/turf/T = get_step_multiz(src, direction)
+		var/opp_dir = dir_inverse_multiz(direction)
 		if(!isopenturf(T))
 			continue
 		if(!(blocks_air || T.blocks_air) && ((direction & (UP|DOWN))? (canvpass && CANVERTICALATMOSPASS(T, src)) : (canpass && CANATMOSPASS(T, src))) )
 			LAZYINITLIST(atmos_adjacent_turfs)
 			LAZYINITLIST(T.atmos_adjacent_turfs)
-			atmos_adjacent_turfs[T] = TRUE
-			T.atmos_adjacent_turfs[src] = TRUE
+			atmos_adjacent_turfs[T] = direction
+			T.atmos_adjacent_turfs[src] = opp_dir
+			T.__update_extools_adjacent_turfs()
 		else
 			if (atmos_adjacent_turfs)
 				atmos_adjacent_turfs -= T
 			if (T.atmos_adjacent_turfs)
 				T.atmos_adjacent_turfs -= src
+				T.__update_extools_adjacent_turfs()
 			UNSETEMPTY(T.atmos_adjacent_turfs)
 	UNSETEMPTY(atmos_adjacent_turfs)
 	src.atmos_adjacent_turfs = atmos_adjacent_turfs
+	__update_extools_adjacent_turfs()
+
+/turf/proc/__update_extools_adjacent_turfs()
+
 
 //returns a list of adjacent turfs that can share air with this one.
 //alldir includes adjacent diagonal tiles that can share
@@ -111,9 +118,9 @@
 	SSair.add_to_active(src,command)
 
 /atom/movable/proc/move_update_air(turf/T)
-	if(isturf(T))
-		T.air_update_turf(1)
-	air_update_turf(1)
+    if(isturf(T))
+        T.air_update_turf(1)
+    air_update_turf(1)
 
 /atom/proc/atmos_spawn_air(text) //because a lot of people loves to copy paste awful code lets just make an easy proc to spawn your plasma fires
 	var/turf/open/T = get_turf(src)
diff --git a/code/modules/atmospherics/environmental/LINDA_turf_tile.dm b/code/modules/atmospherics/environmental/LINDA_turf_tile.dm
index 5a2c46a6dc..dd1b0b4778 100644
--- a/code/modules/atmospherics/environmental/LINDA_turf_tile.dm
+++ b/code/modules/atmospherics/environmental/LINDA_turf_tile.dm
@@ -8,6 +8,7 @@
 	var/list/atmos_adjacent_turfs
 	//bitfield of dirs in which we are superconducitng
 	var/atmos_supeconductivity = NONE
+	var/is_openturf = FALSE // used by extools shizz.
 
 	//used to determine whether we should archive
 	var/archived_cycle = 0
@@ -23,21 +24,21 @@
 	//used for spacewind
 	var/pressure_difference = 0
 	var/pressure_direction = 0
+	var/turf/pressure_specific_target
 
-	var/datum/excited_group/excited_group
-	var/excited = FALSE
 	var/datum/gas_mixture/turf/air
 
 	var/obj/effect/hotspot/active_hotspot
-	var/atmos_cooldown  = 0
 	var/planetary_atmos = FALSE //air will revert to initial_gas_mix over time
 
 	var/list/atmos_overlay_types //gas IDs of current active gas overlays
+	is_openturf = TRUE
 
 /turf/open/Initialize()
 	if(!blocks_air)
 		air = new
 		air.copy_from_turf(src)
+		update_air_ref()
 	. = ..()
 
 /turf/open/Destroy()
@@ -48,6 +49,8 @@
 		SSair.add_to_active(T)
 	return ..()
 
+/turf/proc/update_air_ref()
+
 /////////////////GAS MIXTURE PROCS///////////////////
 
 /turf/open/assume_air(datum/gas_mixture/giver) //use this for machines to adjust air
@@ -93,11 +96,33 @@
 	archived_cycle = SSair.times_fired
 	temperature_archived = temperature
 
+/turf/open/proc/eg_reset_cooldowns()
+/turf/open/proc/eg_garbage_collect()
+/turf/open/proc/get_excited()
+/turf/open/proc/set_excited()
+
 /////////////////////////GAS OVERLAYS//////////////////////////////
 
+
 /turf/open/proc/update_visuals()
-	var/list/new_overlay_types = tile_graphic()
+
 	var/list/atmos_overlay_types = src.atmos_overlay_types // Cache for free performance
+	var/list/new_overlay_types = list()
+	var/static/list/nonoverlaying_gases = typecache_of_gases_with_no_overlays()
+
+	if(!air) // 2019-05-14: was not able to get this path to fire in testing. Consider removing/looking at callers -Naksu
+		if (atmos_overlay_types)
+			for(var/overlay in atmos_overlay_types)
+				vis_contents -= overlay
+			src.atmos_overlay_types = null
+		return
+
+	for(var/id in air.get_gases())
+		if (nonoverlaying_gases[id])
+			continue
+		var/gas_overlay = GLOB.meta_gas_overlays[id]
+		if(gas_overlay && air.get_moles(id) > GLOB.meta_gas_visibility[META_GAS_MOLES_VISIBLE])
+			new_overlay_types += gas_overlay[min(FACTOR_GAS_VISIBLE_MAX, CEILING(air.get_moles(id) / MOLES_GAS_VISIBLE_STEP, 1))]
 
 	if (atmos_overlay_types)
 		for(var/overlay in atmos_overlay_types-new_overlay_types) //doesn't remove overlays that would only be added
@@ -112,18 +137,18 @@
 	UNSETEMPTY(new_overlay_types)
 	src.atmos_overlay_types = new_overlay_types
 
-/turf/open/proc/tile_graphic()
-	var/static/list/nonoverlaying_gases = typecache_of_gases_with_no_overlays()
-	if(!air)
-		return
-	. = new /list
-	for(var/id in air.get_gases())
-		if (nonoverlaying_gases[id])
-			continue
-		var/gas = air.get_moles(id)
-		var/gas_overlay = GLOB.meta_gas_overlays[id]
-		if(gas_overlay && gas > GLOB.meta_gas_visibility[id])
-			. += gas_overlay[min(FACTOR_GAS_VISIBLE_MAX, CEILING(gas / MOLES_GAS_VISIBLE_STEP, 1))]
+/turf/open/proc/set_visuals(list/new_overlay_types)
+	if (atmos_overlay_types)
+		for(var/overlay in atmos_overlay_types-new_overlay_types) //doesn't remove overlays that would only be added
+			vis_contents -= overlay
+
+	if (length(new_overlay_types))
+		if (atmos_overlay_types)
+			vis_contents += new_overlay_types - atmos_overlay_types //don't add overlays that already exist
+		else
+			vis_contents += new_overlay_types
+	UNSETEMPTY(new_overlay_types)
+	src.atmos_overlay_types = new_overlay_types
 
 /proc/typecache_of_gases_with_no_overlays()
 	. = list()
@@ -134,7 +159,7 @@
 
 /////////////////////////////SIMULATION///////////////////////////////////
 
-#define LAST_SHARE_CHECK \
+/*#define LAST_SHARE_CHECK \
 	var/last_share = our_air.get_last_share();\
 	if(last_share > MINIMUM_AIR_TO_SUSPEND){\
 		our_excited_group.reset_cooldowns();\
@@ -143,102 +168,32 @@
 		our_excited_group.dismantle_cooldown = 0;\
 		cached_atmos_cooldown = 0;\
 	}
-
+*/
 /turf/proc/process_cell(fire_count)
 	SSair.remove_from_active(src)
 
-/turf/open/process_cell(fire_count)
-	if(archived_cycle < fire_count) //archive self if not already done
-		archive()
-
-	current_cycle = fire_count
-
-	//cache for sanic speed
-	var/list/adjacent_turfs = atmos_adjacent_turfs
-	var/datum/excited_group/our_excited_group = excited_group
-	var/adjacent_turfs_length = LAZYLEN(adjacent_turfs)
-	var/cached_atmos_cooldown = atmos_cooldown + 1
-
-	var/planet_atmos = planetary_atmos
-	if (planet_atmos)
-		adjacent_turfs_length++
-
-	var/datum/gas_mixture/our_air = air
-
-	for(var/t in adjacent_turfs)
-		var/turf/open/enemy_tile = t
-
-		if(fire_count <= enemy_tile.current_cycle)
+/turf/open/proc/equalize_pressure_in_zone(cyclenum)
+/turf/open/proc/consider_firelocks(turf/T2)
+	var/reconsider_adj = FALSE
+	for(var/obj/machinery/door/firedoor/FD in T2)
+		if((FD.flags_1 & ON_BORDER_1) && get_dir(T2, src) != FD.dir)
 			continue
-		enemy_tile.archive()
+		FD.emergency_pressure_stop()
+		reconsider_adj = TRUE
+	for(var/obj/machinery/door/firedoor/FD in src)
+		if((FD.flags_1 & ON_BORDER_1) && get_dir(src, T2) != FD.dir)
+			continue
+		FD.emergency_pressure_stop()
+		reconsider_adj = TRUE
+	if(reconsider_adj)
+		T2.ImmediateCalculateAdjacentTurfs() // We want those firelocks closed yesterday.
 
-	/******************* GROUP HANDLING START *****************************************************************/
+/turf/proc/handle_decompression_floor_rip()
+/turf/open/floor/handle_decompression_floor_rip(sum)
+	if(sum > 20 && prob(clamp(sum / 10, 0, 30)))
+		remove_tile()
 
-		var/should_share_air = FALSE
-		var/datum/gas_mixture/enemy_air = enemy_tile.air
-
-		//cache for sanic speed
-		var/datum/excited_group/enemy_excited_group = enemy_tile.excited_group
-
-		if(our_excited_group && enemy_excited_group)
-			if(our_excited_group != enemy_excited_group)
-				//combine groups (this also handles updating the excited_group var of all involved turfs)
-				our_excited_group.merge_groups(enemy_excited_group)
-				our_excited_group = excited_group //update our cache
-			should_share_air = TRUE
-
-		else if(our_air.compare(enemy_air))
-			if(!enemy_tile.excited)
-				SSair.add_to_active(enemy_tile)
-			var/datum/excited_group/EG = our_excited_group || enemy_excited_group || new
-			if(!our_excited_group)
-				EG.add_turf(src)
-			if(!enemy_excited_group)
-				EG.add_turf(enemy_tile)
-			our_excited_group = excited_group
-			should_share_air = TRUE
-
-		//air sharing
-		if(should_share_air)
-			var/difference = our_air.share(enemy_air, adjacent_turfs_length)
-			if(difference)
-				if(difference > 0)
-					consider_pressure_difference(enemy_tile, difference)
-				else
-					enemy_tile.consider_pressure_difference(src, -difference)
-			LAST_SHARE_CHECK
-
-
-	/******************* GROUP HANDLING FINISH *********************************************************************/
-
-	if (planet_atmos) //share our air with the "atmosphere" "above" the turf
-		var/datum/gas_mixture/G = new
-		G.copy_from_turf(src)
-		G.archive()
-		if(our_air.compare(G))
-			if(!our_excited_group)
-				var/datum/excited_group/EG = new
-				EG.add_turf(src)
-				our_excited_group = excited_group
-			our_air.share(G, adjacent_turfs_length)
-			LAST_SHARE_CHECK
-
-	SSair.add_to_react_queue(src)
-
-	if((!our_excited_group && !(our_air.return_temperature() > MINIMUM_TEMPERATURE_START_SUPERCONDUCTION && consider_superconductivity(starting = TRUE))) \
-	  || (cached_atmos_cooldown > (EXCITED_GROUP_DISMANTLE_CYCLES * 2)))
-		SSair.remove_from_active(src)
-
-	atmos_cooldown = cached_atmos_cooldown
-
-/turf/proc/process_cell_reaction()
-	SSair.remove_from_react_queue(src)
-
-/turf/open/process_cell_reaction()
-	air.react(src)
-	update_visuals()
-	SSair.remove_from_react_queue(src)
-	return
+/turf/open/process_cell(fire_count)
 
 //////////////////////////SPACEWIND/////////////////////////////
 
@@ -250,17 +205,24 @@
 
 /turf/open/proc/high_pressure_movements()
 	var/atom/movable/M
+	var/multiplier = 1
+	if(locate(/obj/structure/rack) in src)
+		multiplier *= 0.1
+	else if(locate(/obj/structure/table) in src)
+		multiplier *= 0.2
 	for(var/thing in src)
 		M = thing
 		if (!M.anchored && !M.pulledby && M.last_high_pressure_movement_air_cycle < SSair.times_fired)
-			M.experience_pressure_difference(pressure_difference, pressure_direction)
+			M.experience_pressure_difference(pressure_difference * multiplier, pressure_direction, 0, pressure_specific_target)
+	if(pressure_difference > 100)
+		new /obj/effect/temp_visual/dir_setting/space_wind(src, pressure_direction, clamp(round(sqrt(pressure_difference) * 2), 10, 255))
 
 /atom/movable/var/pressure_resistance = 10
 /atom/movable/var/last_high_pressure_movement_air_cycle = 0
 
-/atom/movable/proc/experience_pressure_difference(pressure_difference, direction, pressure_resistance_prob_delta = 0)
+/atom/movable/proc/experience_pressure_difference(pressure_difference, direction, pressure_resistance_prob_delta = 0, throw_target)
 	var/const/PROBABILITY_OFFSET = 25
-	var/const/PROBABILITY_BASE_PRECENT = 75
+	var/const/PROBABILITY_BASE_PRECENT = 10
 	var/max_force = sqrt(pressure_difference)*(MOVE_FORCE_DEFAULT / 5)
 	set waitfor = 0
 	var/move_prob = 100
@@ -268,91 +230,19 @@
 		move_prob = (pressure_difference/pressure_resistance*PROBABILITY_BASE_PRECENT)-PROBABILITY_OFFSET
 	move_prob += pressure_resistance_prob_delta
 	if (move_prob > PROBABILITY_OFFSET && prob(move_prob) && (move_resist != INFINITY) && (!anchored && (max_force >= (move_resist * MOVE_FORCE_PUSH_RATIO))) || (anchored && (max_force >= (move_resist * MOVE_FORCE_FORCEPUSH_RATIO))))
-		step(src, direction)
+		var/move_force = max_force * clamp(move_prob, 0, 100) / 100
+		if(move_force > 4000)
+			// WALLSLAM HELL TIME OH BOY
+			var/turf/throw_turf = get_ranged_target_turf(get_turf(src), direction, round(move_force / 2000))
+			if(throw_target && (get_dir(src, throw_target) & direction))
+				throw_turf = get_turf(throw_target)
+			var/throw_speed = clamp(round(move_force / 2000), 1, 10)
+			throw_at(throw_turf, move_force / 2000, throw_speed)
+		else
+			step(src, direction)
 		last_high_pressure_movement_air_cycle = SSair.times_fired
 
-///////////////////////////EXCITED GROUPS/////////////////////////////
-
-/datum/excited_group
-	var/list/turf_list = list()
-	var/breakdown_cooldown = 0
-	var/dismantle_cooldown = 0
-
-/datum/excited_group/New()
-	SSair.excited_groups += src
-
-/datum/excited_group/proc/add_turf(turf/open/T)
-	turf_list += T
-	T.excited_group = src
-	reset_cooldowns()
-
-/datum/excited_group/proc/merge_groups(datum/excited_group/E)
-	if(turf_list.len > E.turf_list.len)
-		SSair.excited_groups -= E
-		for(var/t in E.turf_list)
-			var/turf/open/T = t
-			T.excited_group = src
-			turf_list += T
-		reset_cooldowns()
-	else
-		SSair.excited_groups -= src
-		for(var/t in turf_list)
-			var/turf/open/T = t
-			T.excited_group = E
-			E.turf_list += T
-		E.reset_cooldowns()
-
-/datum/excited_group/proc/reset_cooldowns()
-	breakdown_cooldown = 0
-	dismantle_cooldown = 0
-
-//argument is so world start can clear out any turf differences quickly.
-/datum/excited_group/proc/self_breakdown(space_is_all_consuming = FALSE)
-	var/datum/gas_mixture/A = new
-
-	//make local for sanic speed
-	var/list/turf_list = src.turf_list
-	var/turflen = turf_list.len
-	var/space_in_group = FALSE
-
-	for(var/t in turf_list)
-		var/turf/open/T = t
-		if (space_is_all_consuming && !space_in_group && istype(T.air, /datum/gas_mixture/immutable/space))
-			space_in_group = TRUE
-			qdel(A)
-			A = new /datum/gas_mixture/immutable/space()
-			break
-		A.merge(T.air)
-
-	A.multiply(1/turflen)
-
-	for(var/t in turf_list)
-		var/turf/open/T = t
-		T.air.copy_from(A)
-		T.atmos_cooldown = 0
-		T.update_visuals()
-
-	breakdown_cooldown = 0
-
-/datum/excited_group/proc/dismantle()
-	for(var/t in turf_list)
-		var/turf/open/T = t
-		T.excited = FALSE
-		T.excited_group = null
-		SSair.active_turfs -= T
-	garbage_collect()
-
-/datum/excited_group/proc/garbage_collect()
-	for(var/t in turf_list)
-		var/turf/open/T = t
-		T.excited_group = null
-	turf_list.Cut()
-	SSair.excited_groups -= src
-
 ////////////////////////SUPERCONDUCTIVITY/////////////////////////////
-/atom/movable/proc/blocksTemperature()
-	return FALSE
-
 /turf/proc/conductivity_directions()
 	if(archived_cycle < SSair.times_fired)
 		archive()
@@ -367,9 +257,6 @@
 			. |= direction
 
 /turf/proc/neighbor_conduct_with_src(turf/open/other)
-	for (var/atom/movable/G in src)
-		if (G.blocksTemperature())
-			return
 	if(!other.blocks_air) //Open but neighbor is solid
 		other.temperature_share_open_to_solid(src)
 	else //Both tiles are solid
@@ -380,9 +267,7 @@
 	if(blocks_air)
 		..()
 		return
-	for (var/atom/movable/G in src)
-		if (G.blocksTemperature())
-			return
+
 	if(!other.blocks_air) //Both tiles are open
 		var/turf/open/T = other
 		T.air.temperature_share(air, WINDOW_HEAT_TRANSFER_COEFFICIENT)
@@ -401,8 +286,10 @@
 
 				if(!neighbor.thermal_conductivity)
 					continue
+
 				if(neighbor.archived_cycle < SSair.times_fired)
 					neighbor.archive()
+
 				neighbor.neighbor_conduct_with_src(src)
 
 				neighbor.consider_superconductivity()
diff --git a/code/modules/atmospherics/machinery/components/binary_devices/dp_vent_pump.dm b/code/modules/atmospherics/machinery/components/binary_devices/dp_vent_pump.dm
index f5c6048b14..d1bb58b99a 100644
--- a/code/modules/atmospherics/machinery/components/binary_devices/dp_vent_pump.dm
+++ b/code/modules/atmospherics/machinery/components/binary_devices/dp_vent_pump.dm
@@ -81,20 +81,17 @@
 				parent1.update = 1
 
 	else //external -> output
-		var/pressure_delta = 10000
+		if(environment.return_pressure() > 0)
+			var/our_multiplier = air2.return_volume() / (environment.return_temperature() * R_IDEAL_GAS_EQUATION)
+			var/moles_delta = 10000 * our_multiplier
+			if(pressure_checks&EXT_BOUND)
+				moles_delta = min(moles_delta, (environment_pressure - output_pressure_max) * environment.return_volume() / (environment.return_temperature() * R_IDEAL_GAS_EQUATION))
+			if(pressure_checks&INPUT_MIN)
+				moles_delta = min(moles_delta, (input_pressure_min - air2.return_pressure()) * our_multiplier)
 
-		if(pressure_checks&EXT_BOUND)
-			pressure_delta = min(pressure_delta, (environment_pressure - external_pressure_bound))
-		if(pressure_checks&INPUT_MIN)
-			pressure_delta = min(pressure_delta, (output_pressure_max - air2.return_pressure()))
-
-		if(pressure_delta > 0)
-			if(environment.return_temperature() > 0)
-				var/transfer_moles = pressure_delta*air2.return_volume()/(environment.return_temperature() * R_IDEAL_GAS_EQUATION)
-
-				var/datum/gas_mixture/removed = loc.remove_air(transfer_moles)
-				//removed can be null if there is no air in the location
-				if(!removed)
+			if(moles_delta > 0)
+				var/datum/gas_mixture/removed = loc.remove_air(moles_delta)
+				if (isnull(removed)) // in space
 					return
 
 				air2.merge(removed)
diff --git a/code/modules/atmospherics/machinery/components/unary_devices/vent_pump.dm b/code/modules/atmospherics/machinery/components/unary_devices/vent_pump.dm
index b6534f5cf7..1a86898f1f 100644
--- a/code/modules/atmospherics/machinery/components/unary_devices/vent_pump.dm
+++ b/code/modules/atmospherics/machinery/components/unary_devices/vent_pump.dm
@@ -113,21 +113,21 @@
 				air_update_turf()
 
 	else // external -> internal
-		var/pressure_delta = 10000
-		if(pressure_checks&EXT_BOUND)
-			pressure_delta = min(pressure_delta, (environment_pressure - external_pressure_bound))
-		if(pressure_checks&INT_BOUND)
-			pressure_delta = min(pressure_delta, (internal_pressure_bound - air_contents.return_pressure()))
+		if(environment.return_pressure() > 0)
+			var/our_multiplier = air_contents.return_volume() / (environment.return_temperature() * R_IDEAL_GAS_EQUATION)
+			var/moles_delta = 10000 * our_multiplier
+			if(pressure_checks&EXT_BOUND)
+				moles_delta = min(moles_delta, (environment_pressure - external_pressure_bound) * environment.return_volume() / (environment.return_temperature() * R_IDEAL_GAS_EQUATION))
+			if(pressure_checks&INT_BOUND)
+				moles_delta = min(moles_delta, (internal_pressure_bound - air_contents.return_pressure()) * our_multiplier)
 
-		if(pressure_delta > 0 && environment.return_temperature() > 0)
-			var/transfer_moles = pressure_delta * air_contents.return_volume() / (environment.return_temperature() * R_IDEAL_GAS_EQUATION)
+			if(moles_delta > 0)
+				var/datum/gas_mixture/removed = loc.remove_air(moles_delta)
+				if (isnull(removed)) // in space
+					return
 
-			var/datum/gas_mixture/removed = loc.remove_air(transfer_moles)
-			if (isnull(removed)) // in space
-				return
-
-			air_contents.merge(removed)
-			air_update_turf()
+				air_contents.merge(removed)
+				air_update_turf()
 	update_parents()
 
 //Radio remote control
diff --git a/code/modules/mapping/reader.dm b/code/modules/mapping/reader.dm
index a792ee280f..11bcc0ffcf 100644
--- a/code/modules/mapping/reader.dm
+++ b/code/modules/mapping/reader.dm
@@ -213,6 +213,7 @@
 	var/list/modelCache = build_cache(no_changeturf)
 	var/space_key = modelCache[SPACE_KEY]
 	var/list/bounds
+	var/did_expand = FALSE
 	src.bounds = bounds = list(1.#INF, 1.#INF, 1.#INF, -1.#INF, -1.#INF, -1.#INF)
 	var/datum/map_orientation_pattern/mode = forced_pattern || GLOB.map_orientation_patterns["[orientation]"] || GLOB.map_orientation_patterns["[SOUTH]"]
 	var/invert_y = mode.invert_y
@@ -235,6 +236,7 @@
 			else
 				while(parsed_z > world.maxz)
 					world.incrementMaxZ()
+					did_expand = TRUE
 			if(!no_changeturf)
 				WARNING("Z-level expansion occurred without no_changeturf set, this may cause problems when /turf/AfterChange is called")
 		//these values are the same until a new gridset is reached.
@@ -256,11 +258,13 @@
 						continue
 					else
 						world.maxx = placement_x
+						did_expand = TRUE
 				if(placement_y > world.maxy)
 					if(cropMap)
 						break
 					else
 						world.maxy = placement_y
+						did_expand = TRUE
 				if(placement_x < 1)
 					actual_x += xi
 					continue
@@ -301,6 +305,9 @@
 		testing("Skipped loading [turfsSkipped] default turfs")
 	#endif
 
+	if(did_expand)
+		world.refresh_atmos_grid()
+
 	return TRUE
 
 /datum/parsed_map/proc/build_cache(no_changeturf, bad_paths=null)