When I was in Junior High School in 1952, the lockers were in banks of 8. Between each bank was a dummy locker, a door without a locker inside. Some kids discovered they could open the dummy locker, crawl inside, climb up and walk inside the wall along the tops of the other lockers in the bank and come down into the next dummy locker. Until the custodians put locks on the dummy lockers.
You could always say "retireded