diff --git a/code/__DEFINES/machines.dm b/code/__DEFINES/machines.dm
index 3a8662dedee..6e4d49aad9f 100644
--- a/code/__DEFINES/machines.dm
+++ b/code/__DEFINES/machines.dm
@@ -126,3 +126,8 @@
 #define AI_DISPLAY_MODE_BLANK 0
 #define AI_DISPLAY_MODE_EMOTE 1
 #define AI_DISPLAY_MODE_BSOD 2
+
+// Door operations
+#define DOOR_OPENING 1
+#define DOOR_CLOSING 2
+#define DOOR_MALF 3
diff --git a/code/__HELPERS/lighting.dm b/code/__HELPERS/lighting.dm
index fcba21227ab..55a0e2e53ec 100644
--- a/code/__HELPERS/lighting.dm
+++ b/code/__HELPERS/lighting.dm
@@ -1,4 +1,4 @@
-/// Produces a mutable appearance glued to the [EMISSIVE_PLANE] dyed to be the [EMISSIVE_COLOR].
+/// Produces a mutable appearance glued to the [EMISSIVE_PLANE] dyed to be the [EMISSIVE_COLOR]. Order of application matters: Default generated blockers are overlays, and will block its own emissive underlays. If you want an object to be both a blocker, and have their own emissive, it has to be an overlay instead. Grayscale lightmasks are visible in the BYOND right-click and Examine pane, unless they're covered up by another overlay.
 /proc/emissive_appearance(icon, icon_state = "", layer = FLOAT_LAYER, alpha = 255, appearance_flags = NONE)
 	var/mutable_appearance/appearance = mutable_appearance(icon, icon_state, layer, EMISSIVE_PLANE, alpha, appearance_flags | EMISSIVE_APPEARANCE_FLAGS)
 	appearance.color = EMISSIVE_COLOR
diff --git a/code/game/area/areas.dm b/code/game/area/areas.dm
index 2519224062e..94e81f2d785 100644
--- a/code/game/area/areas.dm
+++ b/code/game/area/areas.dm
@@ -146,29 +146,34 @@
 	return cameras
 
 /area/proc/air_doors_close()
-	if(!air_doors_activated)
-		air_doors_activated = TRUE
-		for(var/obj/machinery/door/firedoor/D in src)
-			if(!D.welded)
-				D.activate_alarm()
-				if(D.operating)
-					D.nextstate = FD_CLOSED
-				else if(!D.density)
-					spawn(0)
-						D.close()
+	if(air_doors_activated)
+		return
+	air_doors_activated = TRUE
+	for(var/obj/machinery/door/firedoor/D in src)
+		if(!D.is_operational())
+			continue
+		D.activate_alarm()
+		if(D.welded)
+			continue
+		if(D.operating && D.operating != DOOR_CLOSING)
+			D.nextstate = FD_CLOSED
+		else if(!D.density)
+			INVOKE_ASYNC(D, /obj/machinery/door/firedoor.proc/close)
 
 /area/proc/air_doors_open()
-	if(air_doors_activated)
-		air_doors_activated = FALSE
-		for(var/obj/machinery/door/firedoor/D in src)
-			if(!D.welded)
-				D.deactivate_alarm()
-				if(D.operating)
-					D.nextstate = OPEN
-				else if(D.density)
-					spawn(0)
-						D.open()
-
+	if(!air_doors_activated)
+		return
+	air_doors_activated = FALSE
+	for(var/obj/machinery/door/firedoor/D in src)
+		if(!D.is_operational())
+			continue
+		D.deactivate_alarm()
+		if(D.welded)
+			continue
+		if(D.operating && D.operating != DOOR_OPENING)
+			D.nextstate = FD_OPEN
+		else if(D.density)
+			INVOKE_ASYNC(D, /obj/machinery/door/firedoor.proc/open)
 
 /area/Destroy()
 	STOP_PROCESSING(SSobj, src)
@@ -229,23 +234,34 @@
   * Try to close all the firedoors in the area
   */
 /area/proc/ModifyFiredoors(opening)
-	if(firedoors)
-		firedoors_last_closed_on = world.time
-		for(var/FD in firedoors)
-			var/obj/machinery/door/firedoor/D = FD
-			var/cont = !D.welded
-			if(cont && opening)	//don't open if adjacent area is on fire
-				for(var/I in D.affecting_areas)
-					var/area/A = I
-					if(A.fire)
-						cont = FALSE
-						break
-			if(cont && D.is_operational())
-				if(D.operating)
-					D.nextstate = opening ? FD_OPEN : FD_CLOSED
-				else if(!(D.density ^ opening))
-					INVOKE_ASYNC(D, (opening ? /obj/machinery/door/firedoor.proc/open : /obj/machinery/door/firedoor.proc/close))
-					INVOKE_ASYNC(D, (opening ? /obj/machinery/door/firedoor.proc/deactivate_alarm : /obj/machinery/door/firedoor.proc/activate_alarm))
+	if(!firedoors)
+		return
+	firedoors_last_closed_on = world.time
+	for(var/obj/machinery/door/firedoor/D in firedoors)
+		if(!D.is_operational())
+			continue
+		var/valid = TRUE
+		if(opening)	//don't open if adjacent area is on fire
+			for(var/I in D.affecting_areas)
+				var/area/A = I
+				if(A.fire)
+					valid = FALSE
+					break
+		if(!valid)
+			continue
+
+		// At this point, the area is safe and the door is technically functional.
+
+		INVOKE_ASYNC(D, (opening ? /obj/machinery/door/firedoor.proc/deactivate_alarm : /obj/machinery/door/firedoor.proc/activate_alarm)) 
+		if(D.welded)
+			continue // Alarm is toggled, but door stuck
+		if(D.operating)
+			if((D.operating == DOOR_OPENING && opening) || (D.operating == DOOR_CLOSING && !opening))
+				continue
+			else
+				D.nextstate = opening ? FD_OPEN : FD_CLOSED
+		else if(D.density == opening)
+			INVOKE_ASYNC(D, (opening ? /obj/machinery/door/firedoor.proc/open : /obj/machinery/door/firedoor.proc/close))
 
 /**
   * Generate a firealarm alert for this area
diff --git a/code/game/machinery/doors/airlock.dm b/code/game/machinery/doors/airlock.dm
index 644c6c9ae3b..137e19562c7 100644
--- a/code/game/machinery/doors/airlock.dm
+++ b/code/game/machinery/doors/airlock.dm
@@ -1233,7 +1233,7 @@ GLOBAL_LIST_EMPTY(airlock_emissive_underlays)
 	if(!density)
 		return TRUE
 	SEND_SIGNAL(src, COMSIG_AIRLOCK_OPEN)
-	operating = TRUE
+	operating = DOOR_OPENING
 	update_icon(AIRLOCK_OPENING, 1)
 	sleep(1)
 	set_opacity(0)
@@ -1244,7 +1244,7 @@ GLOBAL_LIST_EMPTY(airlock_emissive_underlays)
 	sleep(1)
 	layer = OPEN_DOOR_LAYER
 	update_icon(AIRLOCK_OPEN, 1)
-	operating = FALSE
+	operating = NONE
 	return TRUE
 
 /obj/machinery/door/airlock/close(forced=0, override = 0)
@@ -1274,7 +1274,7 @@ GLOBAL_LIST_EMPTY(airlock_emissive_underlays)
 		killthis.ex_act(EXPLODE_HEAVY)//Smashin windows
 
 	SEND_SIGNAL(src, COMSIG_AIRLOCK_CLOSE)
-	operating = TRUE
+	operating = DOOR_CLOSING
 	update_icon(AIRLOCK_CLOSING, 1)
 	layer = CLOSED_DOOR_LAYER
 	if(!override)
@@ -1290,7 +1290,7 @@ GLOBAL_LIST_EMPTY(airlock_emissive_underlays)
 	update_freelook_sight()
 	sleep(1)
 	update_icon(AIRLOCK_CLOSED, 1)
-	operating = FALSE
+	operating = NONE
 	if(safe)
 		CheckForMobs()
 	return TRUE
@@ -1326,13 +1326,13 @@ GLOBAL_LIST_EMPTY(airlock_emissive_underlays)
 
 /obj/machinery/door/airlock/emag_act(mob/user)
 	if(!operating && density && arePowerSystemsOn() && !emagged)
-		operating = TRUE
+		operating = DOOR_MALF
 		update_icon(AIRLOCK_EMAG, 1)
 		sleep(6)
 		if(QDELETED(src))
 			return
 		electronics = new /obj/item/airlock_electronics/destroyed()
-		operating = FALSE
+		operating = NONE
 		if(!open())
 			update_icon(AIRLOCK_CLOSED, 1)
 		emagged = TRUE
@@ -1341,12 +1341,12 @@ GLOBAL_LIST_EMPTY(airlock_emissive_underlays)
 /obj/machinery/door/airlock/cmag_act(mob/user)
 	if(operating || HAS_TRAIT(src, TRAIT_CMAGGED) || !density || !arePowerSystemsOn())
 		return
-	operating = TRUE
+	operating = DOOR_MALF
 	update_icon(AIRLOCK_EMAG, 1)
 	sleep(6)
 	if(QDELETED(src))
 		return
-	operating = FALSE
+	operating = NONE
 	update_icon(AIRLOCK_CLOSED, 1)
 	ADD_TRAIT(src, TRAIT_CMAGGED, "clown_emag")
 	return TRUE
diff --git a/code/game/machinery/doors/door.dm b/code/game/machinery/doors/door.dm
index c6f82284212..0c442fd217e 100644
--- a/code/game/machinery/doors/door.dm
+++ b/code/game/machinery/doors/door.dm
@@ -14,8 +14,8 @@
 	damage_deflection = 10
 	var/closingLayer = CLOSED_DOOR_LAYER
 	var/visible = TRUE
-	/// Is it currently in the process of opening or closing.
-	var/operating = FALSE
+	/// Is it currently in the process of opening, closing or being tampered
+	var/operating = NONE
 	var/autoclose = FALSE
 	/// Whether the door detects things and mobs in its way and reopen or crushes them.
 	var/safe = TRUE
@@ -383,7 +383,7 @@
 	if(operating)
 		return
 	SEND_SIGNAL(src, COMSIG_DOOR_OPEN)
-	operating = TRUE
+	operating = DOOR_OPENING
 	do_animate("opening")
 	set_opacity(0)
 	sleep(5)
@@ -392,7 +392,7 @@
 	layer = initial(layer)
 	update_icon()
 	set_opacity(0)
-	operating = FALSE
+	operating = NONE
 	air_update_turf(1)
 	update_freelook_sight()
 	if(autoclose)
@@ -413,7 +413,7 @@
 					return
 
 	SEND_SIGNAL(src, COMSIG_DOOR_CLOSE)
-	operating = TRUE
+	operating = DOOR_CLOSING
 
 	do_animate("closing")
 	layer = closingLayer
@@ -423,7 +423,7 @@
 	update_icon()
 	if(!glass || polarized_on)
 		set_opacity(TRUE)
-	operating = FALSE
+	operating = NONE
 	air_update_turf(1)
 	update_freelook_sight()
 	if(safe)
diff --git a/code/game/machinery/doors/firedoor.dm b/code/game/machinery/doors/firedoor.dm
index fc7a37b3b8c..a5ce9b0b5b8 100644
--- a/code/game/machinery/doors/firedoor.dm
+++ b/code/game/machinery/doors/firedoor.dm
@@ -85,8 +85,22 @@
 		latetoggle()
 	else
 		stat |= NOPOWER
+	adjust_light()
 	update_icon()
 
+/obj/machinery/door/firedoor/proc/adjust_light()
+	if(stat & (NOPOWER|BROKEN))
+		set_light(0)
+		return
+	if(active_alarm)
+		set_light(1, 0.5, COLOR_RED_LIGHT)
+	else
+		set_light(1, LIGHTING_MINIMUM_POWER)
+
+/obj/machinery/door/firedoor/extinguish_light()
+	set_light(0)
+	update_icon(UPDATE_OVERLAYS)
+
 /obj/machinery/door/firedoor/attack_hand(mob/user)
 	if(operating || !density)
 		return
@@ -168,7 +182,7 @@
 	else
 		WELDER_WELD_SUCCESS_MESSAGE
 	welded = !welded
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/door/firedoor/try_to_crowbar(obj/item/I, mob/user)
 	if(welded || operating)
@@ -209,20 +223,23 @@
 
 /obj/machinery/door/firedoor/update_overlays()
 	. = ..()
-	if(active_alarm && hasPower())
-		. += image('icons/obj/doors/doorfire.dmi', "alarmlights")
-	if(density && welded)
-		. += "welded"
-		return
 	if(welded)
-		. += "welded_open"
+		. += "welded[density ? "" : "_open"]"
+	if(active_alarm && hasPower())
+		if(light)
+			. += emissive_appearance('icons/obj/doors/doorfire.dmi', "alarmlights_lightmask")
+		. += image('icons/obj/doors/doorfire.dmi', "alarmlights")
 
 /obj/machinery/door/firedoor/proc/activate_alarm()
 	active_alarm = TRUE
+	adjust_light()
 	update_icon()
 
 /obj/machinery/door/firedoor/proc/deactivate_alarm()
 	active_alarm = FALSE
+	if(!density)
+		layer = initial(layer)
+	adjust_light()
 	update_icon()
 
 /obj/machinery/door/firedoor/open(auto_close = TRUE)
@@ -230,7 +247,8 @@
 		return
 	. = ..()
 	latetoggle(auto_close)
-
+	if(active_alarm)
+		layer = closingLayer // Active firedoors take precedence and remain visible over closed airlocks.
 	if(auto_close)
 		autoclose = TRUE
 
@@ -245,13 +263,11 @@
 /obj/machinery/door/firedoor/proc/latetoggle(auto_close = TRUE)
 	if(operating || !hasPower() || !nextstate)
 		return
-	switch(nextstate)
-		if(FD_OPEN)
-			nextstate = null
-			open(auto_close)
-		if(FD_CLOSED)
-			nextstate = null
-			close()
+	if(nextstate == FD_OPEN)
+		INVOKE_ASYNC(src, .proc/open, auto_close)
+	if(nextstate == FD_CLOSED)
+		INVOKE_ASYNC(src, .proc/close)
+	nextstate = null
 
 /obj/machinery/door/firedoor/proc/forcetoggle(magic = FALSE, auto_close = TRUE)
 	if(!magic && (operating || !hasPower()))
diff --git a/code/game/machinery/doors/windowdoor.dm b/code/game/machinery/doors/windowdoor.dm
index 2c0e51f0c22..dc00f7ca1cb 100644
--- a/code/game/machinery/doors/windowdoor.dm
+++ b/code/game/machinery/doors/windowdoor.dm
@@ -178,7 +178,7 @@
 		if(emagged)
 			return 0
 	if(!operating) //in case of emag
-		operating = TRUE
+		operating = DOOR_OPENING
 	do_animate("opening")
 	set_opacity(FALSE)
 	playsound(loc, 'sound/machines/windowdoor.ogg', 100, 1)
@@ -191,7 +191,7 @@
 	update_freelook_sight()
 
 	if(operating) //emag again
-		operating = FALSE
+		operating = NONE
 	return 1
 
 /obj/machinery/door/window/close(forced=0)
@@ -203,7 +203,7 @@
 	if(forced < 2)
 		if(emagged)
 			return 0
-	operating = TRUE
+	operating = DOOR_CLOSING
 	do_animate("closing")
 	playsound(loc, 'sound/machines/windowdoor.ogg', 100, 1)
 	icon_state = base_state
@@ -215,7 +215,7 @@
 	update_freelook_sight()
 	sleep(10)
 
-	operating = FALSE
+	operating = NONE
 	return 1
 
 /obj/machinery/door/window/play_attack_sound(damage_amount, damage_type = BRUTE, damage_flag = 0)
@@ -261,12 +261,12 @@
 /obj/machinery/door/window/emag_act(mob/user, obj/weapon)
 	if(!operating && density && !emagged)
 		emagged = TRUE
-		operating = TRUE
+		operating = DOOR_MALF
 		electronics = new /obj/item/airlock_electronics/destroyed()
 		flick("[base_state]spark", src)
 		playsound(src, "sparks", 75, TRUE, SHORT_RANGE_SOUND_EXTRARANGE)
 		sleep(6)
-		operating = FALSE
+		operating = NONE
 		open(2)
 		return 1
 
@@ -274,11 +274,11 @@
 	if(operating || !density || HAS_TRAIT(src, TRAIT_CMAGGED))
 		return
 	ADD_TRAIT(src, TRAIT_CMAGGED, "clown_emag")
-	operating = TRUE
+	operating = DOOR_MALF
 	flick("[base_state]spark", src)
 	playsound(src, "sparks", 75, TRUE, SHORT_RANGE_SOUND_EXTRARANGE)
 	sleep(6)
-	operating = FALSE
+	operating = NONE
 	return TRUE
 
 /obj/machinery/door/window/attackby(obj/item/I, mob/living/user, params)
diff --git a/icons/obj/doors/doorfire.dmi b/icons/obj/doors/doorfire.dmi
index d154a8436a0..a20b20a1d90 100644
Binary files a/icons/obj/doors/doorfire.dmi and b/icons/obj/doors/doorfire.dmi differ