Fix some runtimes (#2755)

code/game/gamemodes/changeling/changeling_items.dm

@@ -27,7 +27,6 @@
 
 /obj/item/weapon/melee/arm_blade/dropped()
 	visible_message("<span class='danger'>With a sickening crunch, [user] reforms their arm blade into an arm!</span>",
-	"<span class='notice'>We assimilate the weapon back into our body.</span>",
 	"<span class='warning'>You hear organic matter ripping and tearing!</span>")
 	playsound(loc, 'sound/effects/blobattack.ogg', 30, 1)
 	QDEL_IN(src, 1)
@@ -72,7 +71,6 @@
 
 /obj/item/weapon/shield/riot/changeling/dropped()
 	visible_message("<span class='danger'>With a sickening crunch, [user] reforms their arm blade into an arm!</span>",
-	"<span class='notice'>We assimilate the weapon back into our body.</span>",
 	"<span class='warning'>You hear organic matter ripping and tearing!</span>")
 	playsound(loc, 'sound/effects/blobattack.ogg', 30, 1)
 	QDEL_IN(src, 1)

code/modules/client/preferences.dm

@@ -394,7 +394,8 @@ datum/preferences
 
 	for(var/N in character.organs_by_name)
 		var/obj/item/organ/external/O = character.organs_by_name[N]
-		O.markings.Cut()
+		if (O)
+			O.markings.Cut()
 
 	for(var/M in body_markings)
 		var/datum/sprite_accessory/marking/mark_datum = body_marking_styles_list[M]

code/modules/events/spider_infestation.dm

@@ -24,7 +24,7 @@
 
 	while(spawncount && vents.len)
 		var/obj/vent = pick(vents)
-		new /obj/effect/spider/spiderling(vent.loc, spawns = possible_spiders)
+		new /obj/effect/spider/spiderling(vent.loc, null, 1, possible_spiders)
 		vents -= vent
 		spawncount--
 

code/modules/multiz/turf.dm

@@ -114,7 +114,11 @@
  */
 /turf/simulated/open/proc/update()
 	below = GetBelow(src)
-	below.above = src
+
+	// Edge case for when an open turf is above space on the lowest level.
+	if (below)
+		below.above = src
+
 	levelupdate()
 	for (var/atom/movable/A in src)
 		ADD_FALLING_ATOM(A)

code/modules/reagents/Chemistry-Reagents.dm

@@ -34,6 +34,10 @@
 	var/color_weight = 1
 
 /datum/reagent/proc/remove_self(var/amount) // Shortcut
+	if (!holder)
+		PROCLOG_WEIRD("Null holder found. Name: [name], id: [id]")
+		return
+
 	holder.remove_reagent(id, amount)
 
 // This doesn't apply to skin contact - this is for, e.g. extinguishers and sprays. The difference is that reagent is not directly on the mob's skin - it might just be on their clothing.