load the savegame "at restaurant" (url below), go into the restaurant. The waiter gets stuck in his mover and ego can't move until it's done.
http://www.clock.org/~matt/freesci/pq2-save1.zip This keeps the game from being beatable. (As far as I know, anyways -- I never really played this game before. I don't like how restrictive it is in exploring things and talking to people. Asking people about things is really annoying.)
