diff --git a/code/modules/mob/dead/observer/observer.dm b/code/modules/mob/dead/observer/observer.dm
index 2b4a290e2bf..e58df4f1f93 100644
--- a/code/modules/mob/dead/observer/observer.dm
+++ b/code/modules/mob/dead/observer/observer.dm
@@ -422,6 +422,11 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 	if(!MayRespawn(1))
 		return
 
+	var/turf/T = get_turf(src)
+	if(!T || (T.z in config.admin_levels))
+		src << "<span class='warning'>You may not spawn as a mouse on this Z-level.</span>"
+		return
+
 	var/timedifference = world.time - client.time_died_as_mouse
 	if(client.time_died_as_mouse && timedifference <= mouse_respawn_time * 600)
 		var/timedifference_text
@@ -437,8 +442,8 @@ This is the proc mobs get to turn into a ghost. Forked from ghostize due to comp
 	var/mob/living/simple_animal/mouse/host
 	var/obj/machinery/atmospherics/unary/vent_pump/vent_found
 	var/list/found_vents = list()
-	for(var/obj/machinery/atmospherics/unary/vent_pump/v in world)
-		if(!v.welded && v.z == src.z)
+	for(var/obj/machinery/atmospherics/unary/vent_pump/v in machines)
+		if(!v.welded && v.z == T.z)
 			found_vents.Add(v)
 	if(found_vents.len)
 		vent_found = pick(found_vents)