[metmom]

The classroom doors in that school are lever door handles and they open INWARD into the classrooms.

[Still Thinking]

I can’t imagine that that’s not ALREADY a fire code violation, even without locking the doors, unless there’s a door leading directly outside from each classroom (in which case I’m sure they wouldn’t bother locking the hall door in the first place).

OTOH, maybe they didn’t want the doors opening into the hall, blocking other kids who’ve already exited their classrooms, but what I’ve seen done in the past is a little alcove off the hall, so the door can still open out without blocking the hall.