diff --git a/src/g_level.cpp b/src/g_level.cpp
index 0bda657ca..bf47ce58d 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -854,7 +854,7 @@ void G_DoCompleted (void)
 			G_SnapshotLevel ();
 			// Do not free any global strings this level might reference
 			// while it's not loaded.
-			level.Behaviors.LockLevelVarStrings();
+			level.Behaviors.LockLevelVarStrings(level.levelnum);
 		}
 		else
 		{ // Make sure we don't have a snapshot lying around from before.
@@ -1718,7 +1718,7 @@ void G_UnSnapshotLevel (bool hubLoad)
 	if (hubLoad)
 	{
 		// Unlock ACS global strings that were locked when the snapshot was made.
-		level.Behaviors.UnlockLevelVarStrings();
+		level.Behaviors.UnlockLevelVarStrings(level.levelnum);
 	}
 }
 
diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index c85a3c964..577ac1a45 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -687,13 +687,9 @@ public:
 	{
 		GlobalACSStrings.MarkStringArray(&Localvars[0], Localvars.Size());
 	}
-	void LockLocalVarStrings() const
+	void LockLocalVarStrings(int levelnum) const
 	{
-		GlobalACSStrings.LockStringArray(&Localvars[0], Localvars.Size());
-	}
-	void UnlockLocalVarStrings() const
-	{
-		GlobalACSStrings.UnlockStringArray(&Localvars[0], Localvars.Size());
+		GlobalACSStrings.LockStringArray(levelnum, &Localvars[0], Localvars.Size());
 	}
 
 protected:
@@ -929,17 +925,17 @@ FACSStack::~FACSStack()
 
 ACSStringPool GlobalACSStrings;
 
-void ACSStringPool::PoolEntry::Lock()
+void ACSStringPool::PoolEntry::Lock(int levelnum)
 {
-	if (Locks.Find(level.levelnum) == Locks.Size())
+	if (Locks.Find(levelnum) == Locks.Size())
 	{
-		Locks.Push(level.levelnum);
+		Locks.Push(levelnum);
 	}
 }
 
-void ACSStringPool::PoolEntry::Unlock()
+void ACSStringPool::PoolEntry::Unlock(int levelnum)
 {
-	auto ndx = Locks.Find(level.levelnum);
+	auto ndx = Locks.Find(levelnum);
 	if (ndx < Locks.Size())
 	{
 		Locks.Delete(ndx);
@@ -1028,28 +1024,12 @@ const char *ACSStringPool::GetString(int strnum)
 //
 //============================================================================
 
-void ACSStringPool::LockString(int strnum)
+void ACSStringPool::LockString(int levelnum, int strnum)
 {
 	assert((strnum & LIBRARYID_MASK) == STRPOOL_LIBRARYID_OR);
 	strnum &= ~LIBRARYID_MASK;
 	assert((unsigned)strnum < Pool.Size());
-	Pool[strnum].Lock();
-}
-
-//============================================================================
-//
-// ACSStringPool :: UnlockString
-//
-// When equally mated with LockString, allows this string to be purged.
-//
-//============================================================================
-
-void ACSStringPool::UnlockString(int strnum)
-{
-	assert((strnum & LIBRARYID_MASK) == STRPOOL_LIBRARYID_OR);
-	strnum &= ~LIBRARYID_MASK;
-	assert((unsigned)strnum < Pool.Size());
-	Pool[strnum].Unlock();
+	Pool[strnum].Lock(levelnum);
 }
 
 //============================================================================
@@ -1081,7 +1061,7 @@ void ACSStringPool::MarkString(int strnum)
 //
 //============================================================================
 
-void ACSStringPool::LockStringArray(const int *strnum, unsigned int count)
+void ACSStringPool::LockStringArray(int levelnum, const int *strnum, unsigned int count)
 {
 	for (unsigned int i = 0; i < count; ++i)
 	{
@@ -1091,31 +1071,7 @@ void ACSStringPool::LockStringArray(const int *strnum, unsigned int count)
 			num &= ~LIBRARYID_MASK;
 			if ((unsigned)num < Pool.Size())
 			{
-				Pool[num].Lock();
-			}
-		}
-	}
-}
-
-//============================================================================
-//
-// ACSStringPool :: UnlockStringArray
-//
-// Reverse of LockStringArray.
-//
-//============================================================================
-
-void ACSStringPool::UnlockStringArray(const int *strnum, unsigned int count)
-{
-	for (unsigned int i = 0; i < count; ++i)
-	{
-		int num = strnum[i];
-		if ((num & LIBRARYID_MASK) == STRPOOL_LIBRARYID_OR)
-		{
-			num &= ~LIBRARYID_MASK;
-			if ((unsigned)num < Pool.Size())
-			{
-				Pool[num].Unlock();
+				Pool[num].Lock(levelnum);
 			}
 		}
 	}
@@ -2074,26 +2030,26 @@ void FBehaviorContainer::MarkLevelVarStrings()
 	}
 }
 
-void FBehaviorContainer::LockLevelVarStrings()
+void FBehaviorContainer::LockLevelVarStrings(int levelnum)
 {
 	// Lock map variables.
 	for (uint32_t modnum = 0; modnum < StaticModules.Size(); ++modnum)
 	{
-		StaticModules[modnum]->LockMapVarStrings();
+		StaticModules[modnum]->LockMapVarStrings(levelnum);
 	}
 	// Lock running scripts' local variables.
 	if (level.ACSThinker != nullptr)
 	{
 		for (DLevelScript *script = level.ACSThinker->Scripts; script != NULL; script = script->GetNext())
 		{
-			script->LockLocalVarStrings();
+			script->LockLocalVarStrings(levelnum);
 		}
 	}
 }
 
-void FBehaviorContainer::UnlockLevelVarStrings()
+void FBehaviorContainer::UnlockLevelVarStrings(int levelnum)
 {
-	GlobalACSStrings.UnlockForLevel(level.levelnum);
+	GlobalACSStrings.UnlockForLevel(levelnum);
 }
 
 void FBehavior::MarkMapVarStrings() const
@@ -2105,21 +2061,12 @@ void FBehavior::MarkMapVarStrings() const
 	}
 }
 
-void FBehavior::LockMapVarStrings() const
+void FBehavior::LockMapVarStrings(int levelnum) const
 {
-	GlobalACSStrings.LockStringArray(MapVarStore, NUM_MAPVARS);
+	GlobalACSStrings.LockStringArray(levelnum, MapVarStore, NUM_MAPVARS);
 	for (int i = 0; i < NumArrays; ++i)
 	{
-		GlobalACSStrings.LockStringArray(ArrayStore[i].Elements, ArrayStore[i].ArraySize);
-	}
-}
-
-void FBehavior::UnlockMapVarStrings() const
-{
-	GlobalACSStrings.UnlockStringArray(MapVarStore, NUM_MAPVARS);
-	for (int i = 0; i < NumArrays; ++i)
-	{
-		GlobalACSStrings.UnlockStringArray(ArrayStore[i].Elements, ArrayStore[i].ArraySize);
+		GlobalACSStrings.LockStringArray(levelnum, ArrayStore[i].Elements, ArrayStore[i].ArraySize);
 	}
 }
 
diff --git a/src/p_acs.h b/src/p_acs.h
index 14e2bb0a4..0c7f1b583 100644
--- a/src/p_acs.h
+++ b/src/p_acs.h
@@ -102,12 +102,10 @@ public:
 	int AddString(const char *str);
 	int AddString(FString &str);
 	const char *GetString(int strnum);
-	void LockString(int strnum);
-	void UnlockString(int strnum);
+	void LockString(int levelnum, int strnum);
 	void UnlockAll();
 	void MarkString(int strnum);
-	void LockStringArray(const int *strnum, unsigned int count);
-	void UnlockStringArray(const int *strnum, unsigned int count);
+	void LockStringArray(int levelnum, const int *strnum, unsigned int count);
 	void MarkStringArray(const int *strnum, unsigned int count);
 	void MarkStringMap(const FWorldGlobalArray &array);
 	void PurgeStrings();
@@ -134,8 +132,8 @@ private:
 		bool Mark;
 		TArray<int> Locks;
 
-		void Lock();
-		void Unlock();
+		void Lock(int levelnum);
+		void Unlock(int levelnum);
 	};
 	TArray<PoolEntry> Pool;
 	unsigned int PoolBuckets[NUM_BUCKETS];
@@ -419,8 +417,7 @@ private:
 	void SerializeVarSet (FSerializer &arc, int32_t *vars, int max);
 
 	void MarkMapVarStrings() const;
-	void LockMapVarStrings() const;
-	void UnlockMapVarStrings() const;
+	void LockMapVarStrings(int levelnum) const;
 
 	friend void ArrangeScriptProfiles(TArray<ProfileCollector> &profiles);
 	friend void ArrangeFunctionProfiles(TArray<ProfileCollector> &profiles);
@@ -438,8 +435,8 @@ struct FBehaviorContainer
 	FBehavior *GetModule(int lib);
 	void SerializeModuleStates(FSerializer &arc);
 	void MarkLevelVarStrings();
-	void LockLevelVarStrings();
-	void UnlockLevelVarStrings();
+	void LockLevelVarStrings(int levelnum);
+	void UnlockLevelVarStrings(int levelnum);
 
 	const ScriptPtr *FindScript(int script, FBehavior *&module);
 	const char *LookupString(uint32_t index);
@@ -450,4 +447,5 @@ struct FBehaviorContainer
 
 
 
+
 #endif //__P_ACS_H__