Fixes critical crash bugs

code/controllers/subsystems/ai.dm

@@ -39,7 +39,7 @@ SUBSYSTEM_DEF(ai)
 		if(!L?.loc)
 			continue
 
-		if(process_z[get_z(L)] || !L.low_priority) //VOREStation Edit End
+		if((get_z(L) && process_z[get_z(L)]) || !L.low_priority) //VOREStation Edit End
 			A.handle_strategicals()
 		else
 			slept_mobs++

code/controllers/subsystems/mobs.dm

@@ -15,7 +15,7 @@ SUBSYSTEM_DEF(mobs)
 	var/list/currentrun = list()
 	var/log_extensively = FALSE
 	var/list/timelog = list()
-	
+
 	var/slept_mobs = 0
 	var/list/process_z = list()
 
@@ -40,10 +40,10 @@ SUBSYSTEM_DEF(mobs)
 		if(!M || QDELETED(M))
 			mob_list -= M
 			continue
-		else if(M.low_priority && !(M.loc && process_z[get_z(M)]))
+		else if(M.low_priority && !(M.loc && get_z(M) && process_z[get_z(M)]))
 			slept_mobs++
 			continue
-		
+
 		M.Life(times_fired)
 
 		if (MC_TICK_CHECK)
@@ -58,14 +58,14 @@ SUBSYSTEM_DEF(mobs)
 		log_world(msg)
 		return
 	msg += "Lists: currentrun: [currentrun.len], mob_list: [mob_list.len]\n"
-	
+
 	if(!currentrun.len)
 		msg += "!!The subsystem just finished the mob_list list, and currentrun is empty (or has never run).\n"
 		msg += "!!The info below is the tail of mob_list instead of currentrun.\n"
-	
+
 	var/datum/D = currentrun.len ? currentrun[currentrun.len] : mob_list[mob_list.len]
 	msg += "Tail entry: [describeThis(D)] (this is likely the item AFTER the problem item)\n"
-	
+
 	var/position = mob_list.Find(D)
 	if(!position)
 		msg += "Unable to find context of tail entry in mob_list list.\n"