diff --git a/src/p_acs.cpp b/src/p_acs.cpp
index 18ab347eba..cb7da1a53a 100644
--- a/src/p_acs.cpp
+++ b/src/p_acs.cpp
@@ -4598,7 +4598,7 @@ int DLevelScript::CallFunction(int argCount, int funcIndex, SDWORD *args)
 			FName varname(FBehavior::StaticLookupString(args[1]), true);
 			if (varname != NAME_None)
 			{
-				AActor *a = args[0] == 0 ? (AActor *)activator : SingleActorFromTID(args[0], NULL); 
+				AActor *a = SingleActorFromTID(args[0], activator); 
 				return a != NULL ? GetUserVariable(a, varname, 0) : 0;
 			}
 			return 0;
@@ -4637,7 +4637,7 @@ int DLevelScript::CallFunction(int argCount, int funcIndex, SDWORD *args)
 			FName varname(FBehavior::StaticLookupString(args[1]), true);
 			if (varname != NAME_None)
 			{
-				AActor *a = args[0] == 0 ? (AActor *)activator : SingleActorFromTID(args[0], NULL); 
+				AActor *a = SingleActorFromTID(args[0], activator); 
 				return a != NULL ? GetUserVariable(a, varname, args[2]) : 0;
 			}
 			return 0;
@@ -4649,7 +4649,7 @@ int DLevelScript::CallFunction(int argCount, int funcIndex, SDWORD *args)
 
 		case ACSF_CheckActorClass:
 		{
-			AActor *a = args[0] == 0 ? (AActor *)activator : SingleActorFromTID(args[0], NULL);
+			AActor *a = SingleActorFromTID(args[0], activator);
 			return a == NULL ? false : a->GetClass()->TypeName == FName(FBehavior::StaticLookupString(args[1]));
 		}