Fixed walls not splitting zones.

code/ZAS/Zone.dm

@@ -107,6 +107,7 @@ Class Procs:
 	#endif
 
 /zone/proc/rebuild()
+	if(invalid) return //Short circuit for explosions where rebuild is called many times over.
 	c_invalidate()
 	for(var/turf/simulated/T in contents)
 		//T.dbg(invalid_zone)

code/ZAS/_docs.dm

@@ -27,7 +27,7 @@ Notes for people who used ZAS before:
 
 */
 
-//#define ZASDBG
+#define ZASDBG
 //#define ZLEVELS
 
 #define AIR_BLOCKED 1

code/game/turfs/turf.dm

@@ -221,9 +221,11 @@
 	if(connections) connections.erase_all()
 
 	if(istype(src,/turf/simulated))
-		//world << "Removed from zone."
+		//Yeah, we're just going to rebuild the whole thing.
+		//Despite this being called a bunch during explosions,
+		//the zone will only really do heavy lifting once.
 		var/turf/simulated/S = src
-		if(S.zone) S.zone.remove(S)
+		if(S.zone) S.zone.rebuild()
 
 	if(ispath(N, /turf/simulated/floor))
 		//if the old turf had a zone, connect the new turf to it as well - Cael