anchor.diff:      if fUsingDoorway then
       begin
         IncDoorway;
  -      KMUnit.IsExchanging := (fHouse.DoorwayUse > 1);
  +      if fHouse<>nil then
  +        KMUnit.IsExchanging := (fHouse.DoorwayUse > 1);
       end;
       
       fHasStarted:=true;
  
positive.code: destructor TUnitActionGoInOut.Destroy;
  begin
    if fUsedDoorway then DecDoorway;
    Inherited;
  end;
  
  
negative.code:     fLog.AssertToLog(false,'Inc doorway when already in use?');
      exit;
    end;
    if fHouse<>nil then inc(fHouse.DoorwayUse);
    fUsedDoorway := true;
  end;
  
  