Generalizes the 'begin open' airlock behavior.

code/game/machinery/doors/_door.dm

@@ -50,6 +50,9 @@
 	atmos_canpass = CANPASS_PROC
 
 	var/set_dir_on_update = TRUE
+	var/begins_closed     = TRUE
+	var/icon_state_open   = "door0"
+	var/icon_state_closed = "door1"
 
 /obj/machinery/door/proc/can_operate(var/mob/user)
 	. = istype(user) && !user.restrained() && (!issmall(user) || ishuman(user) || issilicon(user) || isbot(user))
@@ -69,6 +72,13 @@
 	if(!populate_parts)
 		inherit_from_assembly(assembly)
 	set_extension(src, /datum/extension/penetration, /datum/extension/penetration/proc_call, .proc/CheckPenetration)
+
+	if(!begins_closed)
+		icon_state = icon_state_open
+		set_density(FALSE)
+		set_opacity(FALSE)
+		layer = open_layer
+
 	..()
 	. = INITIALIZE_HINT_LATELOAD
 
@@ -379,9 +389,9 @@
 
 /obj/machinery/door/on_update_icon()
 	if(density)
-		icon_state = "door1"
+		icon_state = icon_state_closed
 	else
-		icon_state = "door0"
+		icon_state = icon_state_open
 
 	SSradiation.resistance_cache.Remove(get_turf(src))
 
@@ -412,7 +422,7 @@
 	operating = 1
 
 	do_animate("opening")
-	icon_state = "door0"
+	icon_state = icon_state_open
 	set_opacity(FALSE)
 
 	sleep(0.5 SECONDS)

code/game/machinery/doors/airlock.dm

@@ -23,6 +23,9 @@ var/global/list/airlock_overlays = list()
 	base_type = /obj/machinery/door/airlock
 	frame_type = /obj/structure/door_assembly
 
+	icon_state_open   = "open"
+	icon_state_closed = "closed"
+
 	var/aiControlDisabled = 0 //If 1, AI control is disabled until the AI hacks back in and disables the lock. If 2, the AI has bypassed the lock. If -1, the control is enabled but the AI had bypassed it earlier, so if it is disabled again the AI would have no trouble getting back in.
 	var/hackProof = 0 // if 1, this door can't be hacked by the AI
 	var/electrified_until = 0			//World time when the door is no longer electrified. -1 if it is permanently electrified until someone fixes it.
@@ -300,15 +303,15 @@ About the new airlock wires panel:
 	switch(state)
 		if(0)
 			if(density)
-				icon_state = "closed"
+				icon_state = icon_state_closed
 				state = AIRLOCK_CLOSED
 			else
-				icon_state = "open"
+				icon_state = icon_state_open
 				state = AIRLOCK_OPEN
 		if(AIRLOCK_OPEN)
-			icon_state = "open"
+			icon_state = icon_state_open
 		if(AIRLOCK_CLOSED)
-			icon_state = "closed"
+			icon_state = icon_state_closed
 		if(AIRLOCK_OPENING, AIRLOCK_CLOSING, AIRLOCK_EMAG, AIRLOCK_DENY)
 			icon_state = ""
 
@@ -986,6 +989,7 @@ About the new airlock wires panel:
 
 /obj/machinery/door/airlock/Initialize(var/mapload, var/d, var/populate_parts = TRUE, obj/structure/door_assembly/assembly = null)
 	. = ..()
+
 	//wires
 	var/turf/T = get_turf(loc)
 	if(T && isAdminLevel(T.z))
@@ -1003,6 +1007,8 @@ About the new airlock wires panel:
 		if(brace.electronics)
 			brace.req_access = get_req_access()
 		queue_icon_update()
+	else if(!begins_closed)
+		queue_icon_update()
 
 	if (glass)
 		paintable |= PAINT_WINDOW_PAINTABLE

code/game/machinery/doors/airlock_subtypes.dm

@@ -20,12 +20,7 @@
 
 /obj/machinery/door/airlock/medical/open
 	icon_state = "open"
-
-/obj/machinery/door/airlock/medical/open/Initialize()
-	set_density(FALSE)
-	set_opacity(FALSE)
-	layer = open_layer
-	return ..()
+	begins_closed = FALSE
 
 /obj/machinery/door/airlock/virology
 	door_color = COLOR_WHITE
@@ -154,6 +149,10 @@
 		/decl/stock_part_preset/radio/event_transmitter/airlock/external_air = 1
 	)
 
+/obj/machinery/door/airlock/external/open
+	icon_state = "open"
+	begins_closed = FALSE
+
 /obj/machinery/door/airlock/external/get_auto_access()
 	. = ..()
 	var/area/A = get_area(src)

code/game/machinery/doors/blast_door.dm

@@ -15,9 +15,9 @@
 	can_open_manually = FALSE
 
 	// Icon states for different shutter types. Simply change this instead of rewriting the update_icon proc.
-	var/icon_state_open = null
+	icon_state_open = null
+	icon_state_closed = null
 	var/icon_state_opening = null
-	var/icon_state_closed = null
 	var/icon_state_closing = null
 
 	var/icon_state_open_broken = null
@@ -36,7 +36,6 @@
 	//turning this off prevents awkward zone geometry in places like medbay lobby, for example.
 	block_air_zones = 0
 
-	var/begins_closed = TRUE
 	var/decl/material/implicit_material
 	autoset_access = FALSE // Uses different system with buttons.
 	pry_mod = 1.35
@@ -55,15 +54,8 @@
 	base_type = /obj/machinery/door/blast
 
 /obj/machinery/door/blast/Initialize()
-	. = ..()
-
-	if(!begins_closed)
-		icon_state = icon_state_open
-		set_density(0)
-		set_opacity(0)
-		layer = open_layer
-
 	implicit_material = GET_DECL(/decl/material/solid/metal/plasteel)
+	. = ..()
 
 /obj/machinery/door/blast/examine(mob/user)
 	. = ..()