Merge pull request #2953 from comma/master

For for air alarms and bots

code/game/machinery/alarm.dm

@@ -170,10 +170,10 @@
 				visible_message("\The [src] clicks quietly as it stops [environment.temperature > target_temperature ? "cooling" : "heating"] the room.",\
 				"You hear a click as a faint electronic humming stops.")
 
-
+		var/old_level = danger_level
 		danger_level = overall_danger_level()
 
-		if (alarm_area.master_air_alarm == src)
+		if (old_level != danger_level)
 			refresh_danger_level()
 			update_icon()
 

code/game/machinery/bots/medbot.dm

@@ -299,6 +299,7 @@
 	if(src.patient && src.path.len == 0 && (get_dist(src,src.patient) > 1))
 		spawn(0)
 			src.path = AStar(src.loc, get_turf(src.patient), /turf/proc/CardinalTurfsWithAccess, /turf/proc/Distance, 0, 30,id=botcard)
+			if (!path) path = list()
 			if(src.path.len == 0)
 				src.oldpatient = src.patient
 				src.patient = null

code/game/machinery/bots/secbot.dm

@@ -583,7 +583,7 @@ Auto Patrol: []"},
 // given an optional turf to avoid
 /obj/machinery/bot/secbot/proc/calc_path(var/turf/avoid = null)
 	src.path = AStar(src.loc, patrol_target, /turf/proc/CardinalTurfsWithAccess, /turf/proc/Distance, 0, 120, id=botcard, exclude=avoid)
-
+	if (!path) path = list()
 
 // look for a criminal in view of the bot