I don't think it's shown here, but through some wierd exploit it's possible to escape the invisible walls during the infamous Silver fight. He can still grab you through them, though. The thing is, Silver's throw attack isn't programmed to stop and damage you until you hit a physical object, and because the hubworlds don't really have any set vertical boundaries, Silver will literally throw you into the fucking stratosphere if you're not inside the boss boundaries. Hilarious.