Player Z-tracking, again

code/controllers/subsystem/mobs.dm

@@ -1,14 +1,18 @@
 SUBSYSTEM_DEF(mobs)
 	name = "Mobs"
 	priority = 100
-	flags = SS_KEEP_TIMING|SS_NO_INIT
+	flags = SS_KEEP_TIMING
 	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME
 
 	var/list/currentrun = list()
+	var/static/list/clients_by_zlevel[][]
 
 /datum/controller/subsystem/mobs/stat_entry()
 	..("P:[GLOB.mob_living_list.len]")
 
+/datum/controller/subsystem/mobs/Initialize(start_timeofday)
+	clients_by_zlevel = new /list(world.maxz,0)
+	return ..()
 
 /datum/controller/subsystem/mobs/fire(resumed = 0)
 	var/seconds = wait * 0.1