diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 808b724e19..db65f0b702 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -4704,7 +4704,7 @@ bool DLevelScript::DoCheckActorTexture(int tid, AActor *activator, int string, b
 	}
 	else
 	{
-		actor->Sector->NextHighestCeilingAt(actor->X(), actor->Y(), actor->Z(), actor->Top(), 0, &resultsec, &resffloor);
+		NextHighestCeilingAt(actor->Sector, actor->X(), actor->Y(), actor->Z(), actor->Top(), 0, &resultsec, &resffloor);
 		secpic = resffloor ? *resffloor->bottom.texture : resultsec->planes[sector_t::ceiling].Texture;
 	}
 	return tex == TexMan[secpic];
diff --git a/src/p_actionfunctions.cpp b/src/p_actionfunctions.cpp
index 4bb7ade7eb..62726020e5 100644
--- a/src/p_actionfunctions.cpp
+++ b/src/p_actionfunctions.cpp
@@ -582,7 +582,7 @@ DEFINE_ACTION_FUNCTION(AActor, GetZAt)
 					}
 					else
 					{	// [MC] Handle strict 3D floors and portal toggling via the flags passed to it.
-						z = sec->NextHighestCeilingAt(pos.X, pos.Y, mobj->Z(), mobj->Top(), pflags);
+						z = NextHighestCeilingAt(sec, pos.X, pos.Y, mobj->Z(), mobj->Top(), pflags);
 					}
 				}
 				else
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 6ec8323139..8072e6e8fb 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -322,7 +322,7 @@ void P_GetFloorCeilingZ(FCheckPosition &tmf, int flags)
 	sector_t *sec = (!(flags & FFCF_SAMESECTOR) || tmf.thing->Sector == NULL)? P_PointInSector(tmf.pos) : tmf.sector;
 	F3DFloor *ffc, *fff;
 
-	tmf.ceilingz = sec->NextHighestCeilingAt(tmf.pos.X, tmf.pos.Y, tmf.pos.Z, tmf.pos.Z + tmf.thing->Height, flags, &tmf.ceilingsector, &ffc);
+	tmf.ceilingz = NextHighestCeilingAt(sec, tmf.pos.X, tmf.pos.Y, tmf.pos.Z, tmf.pos.Z + tmf.thing->Height, flags, &tmf.ceilingsector, &ffc);
 	tmf.floorz = tmf.dropoffz = sec->NextLowestFloorAt(tmf.pos.X, tmf.pos.Y, tmf.pos.Z, flags, tmf.thing->MaxStepHeight, &tmf.floorsector, &fff);
 
 	if (fff)
diff --git a/src/p_sectors.cpp b/src/p_sectors.cpp
index 6494a202db..a4fdac5d17 100644
--- a/src/p_sectors.cpp
+++ b/src/p_sectors.cpp
@@ -976,9 +976,8 @@ double sector_t::LowestFloorAt(const DVector2 &p, sector_t **resultsec)
 //
 //=====================================================================================
 
-double sector_t::NextHighestCeilingAt(double x, double y, double bottomz, double topz, int flags, sector_t **resultsec, F3DFloor **resultffloor)
+double NextHighestCeilingAt(sector_t *sec, double x, double y, double bottomz, double topz, int flags, sector_t **resultsec, F3DFloor **resultffloor)
 {
-	sector_t *sec = this;
 	double planeheight = -FLT_MAX;
 
 	while (true)
@@ -1003,7 +1002,7 @@ double sector_t::NextHighestCeilingAt(double x, double y, double bottomz, double
 				return ff_bottom;
 			}
 		}
-		if ((flags & FFCF_NOPORTALS) || sec->PortalBlocksMovement(ceiling) || planeheight >= sec->GetPortalPlaneZ(ceiling))
+		if ((flags & FFCF_NOPORTALS) || sec->PortalBlocksMovement(sector_t::ceiling) || planeheight >= sec->GetPortalPlaneZ(sector_t::ceiling))
 		{ // Use sector's ceiling
 			if (resultffloor) *resultffloor = NULL;
 			if (resultsec) *resultsec = sec;
@@ -1011,10 +1010,10 @@ double sector_t::NextHighestCeilingAt(double x, double y, double bottomz, double
 		}
 		else
 		{
-			DVector2 pos = sec->GetPortalDisplacement(ceiling);
+			DVector2 pos = sec->GetPortalDisplacement(sector_t::ceiling);
 			x += pos.X;
 			y += pos.Y;
-			planeheight = sec->GetPortalPlaneZ(ceiling);
+			planeheight = sec->GetPortalPlaneZ(sector_t::ceiling);
 			sec = P_PointInSector(x, y);
 		}
 	}
diff --git a/src/r_defs.h b/src/r_defs.h
index 2214eac299..64def30348 100644
--- a/src/r_defs.h
+++ b/src/r_defs.h
@@ -973,7 +973,6 @@ public:
 		return floorplane.Normal() == -ceilingplane.Normal() && floorplane.D == -ceilingplane.D;
 	}
 
-	double NextHighestCeilingAt(double x, double y, double bottomz, double topz, int flags = 0, sector_t **resultsec = NULL, F3DFloor **resultffloor = NULL);
 	double NextLowestFloorAt(double x, double y, double z, int flags = 0, double steph = 0, sector_t **resultsec = NULL, F3DFloor **resultffloor = NULL);
 
 	// Member variables
@@ -1611,6 +1610,8 @@ double FindShortestUpperAround(sector_t *sector);					// jff 2/04/98
 sector_t *FindModelFloorSector(sector_t *sec, double floordestheight);		// jff 2/04/98
 sector_t *FindModelCeilingSector(sector_t *sec, double floordestheight);		// jff 2/04/98
 
+double NextHighestCeilingAt(sector_t *sec, double x, double y, double bottomz, double topz, int flags = 0, sector_t **resultsec = NULL, F3DFloor **resultffloor = NULL);
+
 // This setup is to allow the VM call directily into the implementation.
 // With a member function this may be subject to OS implementation details, e.g. on Windows 32 bit members use a different calling convention than regular functions.
 void RemoveForceField(sector_t *sec);
diff --git a/src/scripting/backend/vmbuilder.cpp b/src/scripting/backend/vmbuilder.cpp
index fd4ce1c933..c437a60097 100644
--- a/src/scripting/backend/vmbuilder.cpp
+++ b/src/scripting/backend/vmbuilder.cpp
@@ -1081,12 +1081,14 @@ ExpEmit FunctionCallEmitter::EmitCall(VMFunctionBuilder *build, TArray<ExpEmit>
 	}
 
 	assert(returns.Size() < 2 || ReturnRegs != nullptr);
+
+	ExpEmit retreg;
 	for (unsigned i = 0; i < returns.Size(); i++)
 	{
 		ExpEmit reg(build, returns[i].first, returns[i].second);
 		build->Emit(OP_RESULT, 0, EncodeRegType(reg), reg.RegNum);
 		if (ReturnRegs) ReturnRegs->Push(reg);
-		else return reg;
+		else retreg = reg;
 	}
 	if (vm_jit)	// The JIT compiler needs this, but the VM interpreter does not.
 	{
@@ -1097,6 +1099,6 @@ ExpEmit FunctionCallEmitter::EmitCall(VMFunctionBuilder *build, TArray<ExpEmit>
 			reg.Free(build);
 		}
 	}
-	return ExpEmit();
+	return retreg;
 }
 
diff --git a/src/scripting/vmthunks.cpp b/src/scripting/vmthunks.cpp
index 93717fb99b..9230f17925 100644
--- a/src/scripting/vmthunks.cpp
+++ b/src/scripting/vmthunks.cpp
@@ -160,7 +160,7 @@ DEFINE_ACTION_FUNCTION(_Sector, LowestFloorAt)
 	return numret;
 }
 
-DEFINE_ACTION_FUNCTION(_Sector, NextHighestCeilingAt)
+DEFINE_ACTION_FUNCTION_NATIVE(_Sector, NextHighestCeilingAt, NextHighestCeilingAt)
 {
 	PARAM_SELF_STRUCT_PROLOGUE(sector_t);
 	PARAM_FLOAT(x);
@@ -170,21 +170,11 @@ DEFINE_ACTION_FUNCTION(_Sector, NextHighestCeilingAt)
 	PARAM_INT(flags);
 	sector_t *resultsec;
 	F3DFloor *resultff;
-	double resultheight = self->NextHighestCeilingAt(x, y, bottomz, topz, flags, &resultsec, &resultff);
+	double resultheight = NextHighestCeilingAt(self, x, y, bottomz, topz, flags, &resultsec, &resultff);
 
-	if (numret > 2)
-	{
-		ret[2].SetPointer(resultff);
-		numret = 3;
-	}
-	if (numret > 1)
-	{
-		ret[1].SetPointer(resultsec);
-	}
-	if (numret > 0)
-	{
-		ret[0].SetFloat(resultheight);
-	}
+	if (numret > 2) ret[2].SetPointer(resultff);
+	if (numret > 1) ret[1].SetPointer(resultsec);
+	if (numret > 0) ret[0].SetFloat(resultheight);
 	return numret;
 }
 DEFINE_ACTION_FUNCTION(_Sector, NextLowestFloorAt)
@@ -199,19 +189,9 @@ DEFINE_ACTION_FUNCTION(_Sector, NextLowestFloorAt)
 	F3DFloor *resultff;
 	double resultheight = self->NextLowestFloorAt(x, y, z, flags, steph, &resultsec, &resultff);
 
-	if (numret > 2)
-	{
-		ret[2].SetPointer(resultff);
-		numret = 3;
-	}
-	if (numret > 1)
-	{
-		ret[1].SetPointer(resultsec);
-	}
-	if (numret > 0)
-	{
-		ret[0].SetFloat(resultheight);
-	}
+	if (numret > 2) ret[2].SetPointer(resultff);
+	if (numret > 1) ret[1].SetPointer(resultsec);
+	if (numret > 0) ret[0].SetFloat(resultheight);
 	return numret;
 }