Fixes new player runtime that makes people unable to join rounds.

code/modules/mob/dead/new_player/new_player.dm

@@ -444,6 +444,8 @@
 		if(job && IsJobUnavailable(job.title, TRUE) == JOB_AVAILABLE)
 			available_job_count++
 	for(var/spawner in GLOB.mob_spawners)
+		if(!LAZYLEN(spawner))
+			continue
 		var/obj/effect/mob_spawn/S = pick(GLOB.mob_spawners[spawner])
 		if(!istype(S) || !S.can_latejoin())
 			continue
@@ -468,6 +470,8 @@
 			"Security" = list(jobs = list(), titles = GLOB.security_positions, color = "#ff9999"),
 		)
 		for(var/spawner in GLOB.mob_spawners)
+			if(!LAZYLEN(spawner))
+				continue
 			var/obj/effect/mob_spawn/S = pick(GLOB.mob_spawners[spawner])
 			if(!istype(S) || !S.can_latejoin())
 				continue