Go into the teleporter on Kino Der Toten and when you are throwing grenades or shooting out of the window in the pack of punch room, jump on the window and in mid air press B so you're crouching.

If done right you should be on the window, then scoot forward a bit and when its time for you to go, the teleporter won't take you.

You'll be stuck up there the whole game but when the teleporter tries to take you away and fails you can get out of the window (just make sure the teleporter doesnt take you away!).