Refined earlier fix

Tried a couple of other solutions, but this ended up being the most reliable.

Now checks all areas associated with the firedoor to see if they should still be down.

Also makes a final check before closing the door in case the fire alarm turns off in the middle of an autoclose cycle.

code/game/area/areas.dm

@@ -100,6 +100,7 @@
 		return
 	if( !fire )
 		fire = 1
+		master.fire = 1		//used for firedoor checks
 		updateicon()
 		mouse_opacity = 0
 		for(var/obj/machinery/door/firedoor/D in all_doors)
@@ -122,6 +123,7 @@
 /area/proc/firereset()
 	if (fire)
 		fire = 0
+		master.fire = 0		//used for firedoor checks
 		mouse_opacity = 0
 		updateicon()
 		for(var/obj/machinery/door/firedoor/D in all_doors)

code/game/machinery/doors/firedoor.dm

@@ -88,12 +88,11 @@
 		user << "<span class='warning'>Access denied.</span>"
 		return
 
-	var/area/A = get_area(src)
-	ASSERT(istype(A))
-	/*if(A.master)		// var/fire in master area never gets set, so will always be 0
-		A = A.master*/
+	var/alarmed = 0
 
-	var/alarmed = (A.air_doors_activated || A.fire)
+	for(var/area/A in areas_added)		//Checks if there are fire alarms in any areas associated with that firedoor
+		if(A.fire || A.air_doors_activated)
+			alarmed = 1
 
 	var/answer = alert(user, "Would you like to [density ? "open" : "close"] this [src.name]?[ alarmed && density ? "\nNote that by doing so, you acknowledge any damages from opening this\n[src.name] as being your own fault, and you will be held accountable under the law." : ""]",\
 	"\The [src]", "Yes, [density ? "open" : "close"]", "No")
@@ -115,6 +114,10 @@
 
 	if(needs_to_close)
 		spawn(50)
+			alarmed = 0
+			for(var/area/A in areas_added)		//Just in case a fire alarm is turned off while the firedoor is going through an autoclose cycle
+				if(A.fire || A.air_doors_activated)
+					alarmed = 1
 			if(alarmed)
 				nextstate = CLOSED
 				close()