Merge pull request #2743 from SkyMarshal/bleeding-edge-freeze

Fixes some runtimes as well as a merge-related bug that made heat not transfer through doors.

code/ZAS/Functions.dm

@@ -63,6 +63,10 @@ proc/FloodFill(turf/simulated/start)
 
 
 proc/ZMerge(zone/A,zone/B)
+
+	if(!istype(A) || !istype(B))
+		return
+
 	//Merges two zones so that they are one.
 	var
 		a_size = A.air.group_multiplier
@@ -127,8 +131,6 @@ proc/ZConnect(turf/simulated/A,turf/simulated/B)
 	if(!A.zone || !B.zone) return
 	if(A.zone == B.zone) return
 
-	if(!A.CanPass(null,B,0,0)) return
-
 	if(A.CanPass(null,B,0,1))
 		return ZMerge(A.zone,B.zone)
 

code/ZAS/Plasma.dm

@@ -155,6 +155,8 @@ turf/Entered(obj/item/I)
 	//Items that are in plasma, but not on a mob, can still be contaminated.
 	if(istype(I) && vsc.plc.CLOTH_CONTAMINATION)
 		var/datum/gas_mixture/env = return_air(1)
+		if(!env)
+			return
 		if(env.toxins > MOLES_PLASMA_VISIBLE + 1)
 			if(I.can_contaminate())
 				I.contaminate()