Just because you were able to get in, that does not mean you will be able to get out. Entrances do not became exits, and there is nothing to guarantee that the door you walked through a moment ago will still be there when you turn around to look for it again. That is how it works in the city. Every time you think you know the answer to a question, you discover that the question makes no sense.

Paul Auster in In the country of last things.