diff --git a/src/g_strife/a_strifeitems.cpp b/src/g_strife/a_strifeitems.cpp
index 45e8218e1..26ac88393 100644
--- a/src/g_strife/a_strifeitems.cpp
+++ b/src/g_strife/a_strifeitems.cpp
@@ -188,10 +188,13 @@ bool ARaiseAlarm::TryPickup (AActor *&toucher)
 
 bool ARaiseAlarm::SpecialDropAction (AActor *dropper)
 {
-	P_NoiseAlert (dropper->target, dropper->target);
-	if (dropper->target->CheckLocalView (consoleplayer))
+	if (dropper->target != nullptr)
 	{
-		Printf ("You Fool!  You've set off the alarm.\n");
+		P_NoiseAlert(dropper->target, dropper->target);
+		if (dropper->target->CheckLocalView(consoleplayer))
+		{
+			Printf("You Fool!  You've set off the alarm.\n");
+		}
 	}
 	Destroy ();
 	return true;
@@ -237,11 +240,14 @@ bool ACloseDoor222::TryPickup (AActor *&toucher)
 bool ACloseDoor222::SpecialDropAction (AActor *dropper)
 {
 	EV_DoDoor (DDoor::doorClose, NULL, dropper, 222, 2., 0, 0, 0);
-	if (dropper->target->CheckLocalView (consoleplayer))
+	if (dropper->target != nullptr)
 	{
-		Printf ("You're dead!  You set off the alarm.\n");
+		if (dropper->target->CheckLocalView(consoleplayer))
+		{
+			Printf("You're dead!  You set off the alarm.\n");
+		}
+		P_NoiseAlert(dropper->target, dropper->target);
 	}
-	P_NoiseAlert (dropper->target, dropper->target);
 	Destroy ();
 	return true;
 }
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 22004b897..8fd274437 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -1140,7 +1140,7 @@ bool PIT_CheckThing(FMultiBlockThingsIterator &it, FMultiBlockThingsIterator::Ch
 			DVector3 oldpos = tm.thing->PosRelative(thing);
 			// Both actors already overlap. To prevent them from remaining stuck allow the move if it
 			// takes them further apart or the move does not change the position (when called from P_ChangeSector.)
-			if (oldpos.X == thing->X() && oldpos.Y == thing->Y())
+			if (tm.pos.X == tm.thing->X() && tm.pos.Y == tm.thing->Y())
 			{
 				unblocking = true;
 			}
@@ -5487,7 +5487,7 @@ void P_FindAboveIntersectors(AActor *actor)
 			// not what is wanted here.
 			continue;
 		}
-		if (thing->Z() >= actor->Z() &&
+		if (thing->Z() > actor->Z() &&
 			thing->Z() <= actor->Top())
 		{ // Thing intersects above the base
 			intersectors.Push(thing);
diff --git a/src/p_maputl.cpp b/src/p_maputl.cpp
index 552889c48..5fa8aa2f2 100644
--- a/src/p_maputl.cpp
+++ b/src/p_maputl.cpp
@@ -459,6 +459,8 @@ void AActor::LinkToWorld(bool spawningmapthing, sector_t *sector)
 
 		P_CollectConnectedGroups(Sector->PortalGroup, Pos(), Top(), radius, check);
 
+		BlockNode = NULL;
+		FBlockNode **alink = &this->BlockNode;
 		for (int i = -1; i < (int)check.Size(); i++)
 		{
 			DVector3 pos = i==-1? Pos() : PosRelative(check[i] & ~FPortalGroupArray::FLAT);
@@ -470,11 +472,9 @@ void AActor::LinkToWorld(bool spawningmapthing, sector_t *sector)
 
 			if (x1 >= bmapwidth || x2 < 0 || y1 >= bmapheight || y2 < 0)
 			{ // thing is off the map
-				BlockNode = NULL;
 			}
 			else
 			{ // [RH] Link into every block this actor touches, not just the center one
-				FBlockNode **alink = &this->BlockNode;
 				x1 = MAX(0, x1);
 				y1 = MAX(0, y1);
 				x2 = MIN(bmapwidth - 1, x2);