diff --git a/src/p_map.cpp b/src/p_map.cpp
index e7aceba78..ec9fea20a 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -4439,6 +4439,9 @@ AActor *P_LinePickActor(AActor *t1, DAngle angle, double distance, DAngle pitch,
 	
 	TData.Caller = t1;
 	TData.hitGhosts = true;
+	TData.MThruSpecies = false;
+	TData.ThruActors = false;
+	TData.ThruSpecies = false;
 	
 	if (Trace(t1->PosAtZ(shootz), t1->Sector, direction, distance,
 		actorMask, wallMask, t1, trace, TRACE_NoSky | TRACE_PortalRestrict, CheckForActor, &TData))
diff --git a/src/po_man.cpp b/src/po_man.cpp
index 001f308f1..e449e0d67 100644
--- a/src/po_man.cpp
+++ b/src/po_man.cpp
@@ -1327,6 +1327,17 @@ void FPolyObj::RecalcActorFloorCeil(FBoundingBox bounds) const
 
 	while ((actor = it.Next()) != NULL)
 	{
+		// skip everything outside the bounding box.
+		if (actor->X() + actor->radius <= bounds.Left() ||
+			actor->X() - actor->radius >= bounds.Right() ||
+			actor->Y() + actor->radius <= bounds.Bottom() ||
+			actor->Y() - actor->radius >= bounds.Top())
+		{
+			continue;
+		}
+		// Todo: Be a little more thorough with what gets altered here
+		// because this can dislocate a lot of items that were spawned on 
+		// the lower side of a sector boundary.
 		P_FindFloorCeiling(actor);
 	}
 }