most prisons do NOT have walls, they have woven wire fences. Only the inside fence has a motion sensor on it. The outside one, your buddy can cut thru as fast and sloppily as he wants. The inside one, you have to slowly, carefully, cut a 2 ft square section out of, and remove it, then BOTH of you start cutting and removing sections of the coiled razor wire. Take about 5 minutes, but a fight, fire, etc on the OTHER side of the prison will "buy" five minutes, often and easily. A tunnel, from the OUTSIDE in, would be a fairly safe, simple (if long, slow process) too,from some nearby building or other unseen area (like a ditch culvert, behind a big hill, bunch of trees, etc.