diff --git a/code/modules/vehicles/_vehicle.dm b/code/modules/vehicles/_vehicle.dm
index a968d42073..4925cf40e7 100644
--- a/code/modules/vehicles/_vehicle.dm
+++ b/code/modules/vehicles/_vehicle.dm
@@ -54,7 +54,7 @@
 	return occupants
 
 /obj/vehicle/proc/occupant_amount()
-	return length(occupants)
+	return LAZYLEN(occupants)
 
 /obj/vehicle/proc/return_amount_of_controllers_with_flag(flag)
 	. = 0
@@ -82,9 +82,10 @@
 	return !isnull(occupants[M])
 
 /obj/vehicle/proc/add_occupant(mob/M, control_flags)
-	if(!istype(M) || occupants[M])
+	if(!istype(M) || is_occupant(M))
 		return FALSE
-	occupants[M] = NONE
+
+	LAZYSET(occupants, M, NONE)
 	add_control_flags(M, control_flags)
 	after_add_occupant(M)
 	grant_passenger_actions(M)
@@ -102,7 +103,7 @@
 		return FALSE
 	remove_control_flags(M, ALL)
 	remove_passenger_actions(M)
-	occupants -= M
+	LAZYREMOVE(occupants, M)
 	cleanup_actions_for_mob(M)
 	after_remove_occupant(M)
 	return TRUE
@@ -140,7 +141,7 @@
 	return
 
 /obj/vehicle/proc/add_control_flags(mob/controller, flags)
-	if(!istype(controller) || !flags)
+	if(!is_occupant(controller) || !flags)
 		return FALSE
 	occupants[controller] |= flags
 	for(var/i in GLOB.bitflags)
@@ -149,7 +150,7 @@
 	return TRUE
 
 /obj/vehicle/proc/remove_control_flags(mob/controller, flags)
-	if(!istype(controller) || !flags)
+	if(!is_occupant(controller) || !flags)
 		return FALSE
 	occupants[controller] &= ~flags
 	for(var/i in GLOB.bitflags)
diff --git a/code/modules/vehicles/cars/car.dm b/code/modules/vehicles/cars/car.dm
index 4e9595c7dc..c676a63a35 100644
--- a/code/modules/vehicles/cars/car.dm
+++ b/code/modules/vehicles/cars/car.dm
@@ -45,7 +45,7 @@
 	return ..()
 
 /obj/vehicle/sealed/car/mob_try_exit(mob/M, mob/user, silent = FALSE)
-	if(M == user && (occupants[M] & VEHICLE_CONTROL_KIDNAPPED))
+	if(M == user && (LAZYACCESS(occupants, M) & VEHICLE_CONTROL_KIDNAPPED))
 		to_chat(user, "<span class='notice'>You push against the back of [src] trunk to try and get out.</span>")
 		if(!do_after(user, escape_time, target = src))
 			return FALSE
@@ -73,7 +73,7 @@
 	if(do_after(user, 30))
 		if(return_amount_of_controllers_with_flag(VEHICLE_CONTROL_KIDNAPPED))
 			to_chat(user, "<span class='notice'>The people stuck in [src]'s trunk all come tumbling out.</span>")
-			DumpSpecificMobs(VEHICLE_CONTROL_KIDNAPPED)
+			dump_specific_mobs(VEHICLE_CONTROL_KIDNAPPED)
 		else
 			to_chat(user, "<span class='notice'>It seems [src]'s trunk was empty.</span>")
 
diff --git a/code/modules/vehicles/mecha/_mecha.dm b/code/modules/vehicles/mecha/_mecha.dm
index e305d4830d..163bc13cf8 100644
--- a/code/modules/vehicles/mecha/_mecha.dm
+++ b/code/modules/vehicles/mecha/_mecha.dm
@@ -459,7 +459,7 @@
 				transfer_moles = pressure_delta*cabin_air.return_volume()/(cabin_air.return_temperature() * R_IDEAL_GAS_EQUATION)
 				cabin_air.transfer_to(t_air, transfer_moles)
 
-	if(occupants)
+	if(LAZYLEN(occupants))
 		for(var/i in occupants)
 			var/mob/living/occupant = i
 			if(cell)
@@ -908,13 +908,14 @@
 
 ///Handles an actual AI (simple_animal mecha pilot) entering the mech
 /obj/vehicle/sealed/mecha/proc/aimob_enter_mech(mob/living/simple_animal/hostile/syndicate/mecha_pilot/pilot_mob)
-	if(pilot_mob && pilot_mob.Adjacent(src))
-		if(LAZYLEN(occupants))
-			return
-		LAZYADD(occupants, src)
-		pilot_mob.mecha = src
-		pilot_mob.forceMove(src)
-		update_icon()
+	if(!pilot_mob?.Adjacent(src))
+		return
+	if(LAZYLEN(occupants))
+		return
+	LAZYSET(occupants, pilot_mob, NONE)
+	pilot_mob.mecha = src
+	pilot_mob.forceMove(src)
+	update_icon()
 
 ///Handles an actual AI (simple_animal mecha pilot) exiting the mech
 /obj/vehicle/sealed/mecha/proc/aimob_exit_mech(mob/living/simple_animal/hostile/syndicate/mecha_pilot/pilot_mob)
diff --git a/code/modules/vehicles/mecha/combat/durand.dm b/code/modules/vehicles/mecha/combat/durand.dm
index bc83bfcfec..d351300764 100644
--- a/code/modules/vehicles/mecha/combat/durand.dm
+++ b/code/modules/vehicles/mecha/combat/durand.dm
@@ -177,7 +177,7 @@ own integrity back to max. Shield is automatically dropped if we run out of powe
 /obj/durand_shield/proc/activate(datum/source, mob/owner, list/signal_args)
 	SIGNAL_HANDLER
 	currentuser = owner
-	if(!chassis?.occupants)
+	if(!LAZYLEN(chassis?.occupants))
 		return
 	if(switching && !signal_args[1])
 		return
diff --git a/code/modules/vehicles/mecha/equipment/mecha_equipment.dm b/code/modules/vehicles/mecha/equipment/mecha_equipment.dm
index 87515cb940..fa379e2615 100644
--- a/code/modules/vehicles/mecha/equipment/mecha_equipment.dm
+++ b/code/modules/vehicles/mecha/equipment/mecha_equipment.dm
@@ -41,7 +41,7 @@
 			chassis.selected = null
 		update_chassis_page()
 		log_message("[src] is destroyed.", LOG_MECHA)
-		if(chassis.occupants)
+		if(!LAZYLEN(chassis?.occupants))
 			to_chat(chassis.occupants, "[icon2html(src, chassis.occupants)]<span class='danger'>[src] is destroyed!</span>")
 			playsound(chassis, destroy_sound, 50)
 		if(!detachable) //If we're a built-in nondetachable equipment, let's lock up the slot that we were in.
diff --git a/code/modules/vehicles/mecha/equipment/tools/mining_tools.dm b/code/modules/vehicles/mecha/equipment/tools/mining_tools.dm
index 46190a4c84..7ce7cc2e2c 100644
--- a/code/modules/vehicles/mecha/equipment/tools/mining_tools.dm
+++ b/code/modules/vehicles/mecha/equipment/tools/mining_tools.dm
@@ -173,8 +173,7 @@
 		STOP_PROCESSING(SSfastprocess, src)
 		qdel(src)
 	if(istype(loc, /obj/vehicle/sealed/mecha/working) && scanning_time <= world.time)
-		var/obj/vehicle/sealed/mecha/working/mecha = loc
-		if(!mecha.occupants)
+		if(!LAZYLEN(chassis?.occupants))
 			return
 		scanning_time = world.time + equip_cooldown
 		mineral_scan_pulse(get_turf(src))
diff --git a/code/modules/vehicles/mecha/mecha_defense.dm b/code/modules/vehicles/mecha/mecha_defense.dm
index 8bdb38abc3..151e27d2d7 100644
--- a/code/modules/vehicles/mecha/mecha_defense.dm
+++ b/code/modules/vehicles/mecha/mecha_defense.dm
@@ -156,7 +156,7 @@
 		for(var/occus in occupants)
 			var/mob/living/occupant = occus
 			occupant.update_mouse_pointer()
-	if(!equipment_disabled && occupants) //prevent spamming this message with back-to-back EMPs
+	if(!equipment_disabled && LAZYLEN(occupants)) //prevent spamming this message with back-to-back EMPs
 		to_chat(occupants, "<span=danger>Error -- Connection to equipment control unit has been lost.</span>")
 	addtimer(CALLBACK(src, TYPE_PROC_REF(/obj/vehicle/sealed/mecha, restore_equipment)), 3 SECONDS, TIMER_UNIQUE | TIMER_OVERRIDE)
 	equipment_disabled = 1
diff --git a/code/modules/vehicles/sealed.dm b/code/modules/vehicles/sealed.dm
index 7c1fa8f61a..cea6368f7a 100644
--- a/code/modules/vehicles/sealed.dm
+++ b/code/modules/vehicles/sealed.dm
@@ -98,13 +98,14 @@
 			var/mob/living/carbon/Carbon = i
 			Carbon.DefaultCombatKnockdown(40)
 
-/obj/vehicle/sealed/proc/DumpSpecificMobs(flag, randomstep = TRUE)
+/obj/vehicle/sealed/proc/dump_specific_mobs(flag, randomstep = TRUE)
 	for(var/i in occupants)
-		if((occupants[i] & flag))
-			mob_exit(i, null, randomstep)
-			if(iscarbon(i))
-				var/mob/living/carbon/C = i
-				C.DefaultCombatKnockdown(40)
+		if(!(occupants[i] & flag))
+			continue
+		mob_exit(i, null, randomstep)
+		if(iscarbon(i))
+			var/mob/living/carbon/C = i
+			C.DefaultCombatKnockdown(40)
 
 
 /obj/vehicle/sealed/AllowDrop()
diff --git a/code/modules/vehicles/vehicle_actions.dm b/code/modules/vehicles/vehicle_actions.dm
index e0c29a35b9..28d469d518 100644
--- a/code/modules/vehicles/vehicle_actions.dm
+++ b/code/modules/vehicles/vehicle_actions.dm
@@ -21,7 +21,7 @@
 		grant_controller_actions(i)	//refresh
 
 /obj/vehicle/proc/grant_action_type_to_mob(actiontype, mob/m)
-	if(isnull(occupants[m]) || !actiontype)
+	if(isnull(LAZYACCESS(occupants, m)) || !actiontype)
 		return FALSE
 	LAZYINITLIST(occupant_actions[m])
 	if(occupant_actions[m][actiontype])
@@ -32,7 +32,7 @@
 	return TRUE
 
 /obj/vehicle/proc/remove_action_type_from_mob(actiontype, mob/m)
-	if(isnull(occupants[m]) || !actiontype)
+	if(isnull(LAZYACCESS(occupants, m)) || !actiontype)
 		return FALSE
 	LAZYINITLIST(occupant_actions[m])
 	if(occupant_actions[m][actiontype])
@@ -50,7 +50,7 @@
 		remove_action_type_from_mob(v, M)
 
 /obj/vehicle/proc/grant_controller_actions(mob/M)
-	if(!istype(M) || isnull(occupants[M]))
+	if(!istype(M) || isnull(LAZYACCESS(occupants, M)))
 		return FALSE
 	for(var/i in GLOB.bitflags)
 		if(occupants[M] & i)
@@ -58,7 +58,7 @@
 	return TRUE
 
 /obj/vehicle/proc/remove_controller_actions(mob/M)
-	if(!istype(M) || isnull(occupants[M]))
+	if(!istype(M) || isnull(LAZYACCESS(occupants, M)))
 		return FALSE
 	for(var/i in GLOB.bitflags)
 		remove_controller_actions_by_flag(M, i)
@@ -145,8 +145,7 @@
 
 /datum/action/vehicle/sealed/dump_kidnapped_mobs/Trigger()
 	vehicle_entered_target.visible_message(span_danger("[vehicle_entered_target] starts dumping the people inside of it."))
-	vehicle_entered_target.DumpSpecificMobs(VEHICLE_CONTROL_KIDNAPPED)
-
+	vehicle_entered_target.dump_specific_mobs(VEHICLE_CONTROL_KIDNAPPED)
 
 /datum/action/vehicle/sealed/roll_the_dice
 	name = "Press Colorful Button"