fire
Having the doors chained was unconscionable. Think what that would have been like if there had in fact been a fire. It seems dishonest of the film's story to not have seriously dealt with that, but instead presenting the chained doors as if they were only a safety problem in the eyes of a few dissatisfied outsiders.
Granted, there was a drug problem, but surely there are other ways of handling it than setting up a deadly risk. For instance, he could have asked for parent volunteers to guard the doors.