Welcome to the boards and thanks for the post. If you do a search, you'll find a pretty long thread on just this topic. You are correct that they only move a few inches - however, they don't actually travel at all. They simply vibrate and move up and down just enough to give you the sensation of it starting and stopping. You enter and exit the elevator at the exact same ground level.
Oh, i searched but didnt see. These forums look great. Im going to disneyworld May 27th. cant wait. DIsney rules! thanks for the welcome. Anyways, Yeah, they said the walls only move. Hmm...