Don't know if it is an option,
but i have seen some tutorial-skp's, where there was a model in scene 1, and scene 2 was looking at a (changed) cópy of that same model which was located a bit to the right so you did not see that one when you were looking at scene 1.
If you change to scene 2, scene one is leaving your screen and you see the changed model.
(but ofcourse you won't see the doors getting opened in 1 model, you will just see model 1 dissappearing and model 2 appearing and this is probably not what you were looking for?)