Pandemonium spawns as the lights flicker, his warning call heard from afar as you approach the locker... When you enter, Pandemonium engages his attack, pulling up to your locker and making you play a game where you have to keep the locker shut via keeping a circle in a zone. Pandemonium bangs on the locker, knocking the circle out of place, resulting in you putting it back in the zone and repeating it over and over for a minute before he gave up and left. You are safe.