They didn’t have locks but you could probably break the hinges on the door in a way that it doesn’t open, maybe? I’ve only ever seen like a folding door (double hinged) design. Maybe some pennies? It’d work for a normal door, not sure about the accordion style tho.
There’s a movie called “Phonebooth” that has a dude trapped in a phonebooth because a sniper is watching him and blackmailing him because he’s cheating on his wife/fiance. That’s the most notable a thing I know involving a phone booth other than Dr. Who.
Used to be a college challenge to stuff as many people in one as possible; I bet you could find a horror story or two stemming from that, perhaps.