If there were three people in the airplane bathroom I would think that it's possible that they couldn't come out, not wouldn't.
Perhaps someone unexpectedly gave birth to twins?
But seriesly, why don’t airplane lavatories have a simple, exterior, crew-operated latch for these situations ... not to mention those where an innocent passenger goes into a catatonic state of claustrophobia or is too drunk to figure out the latch from inside?
“If there were three people in the airplane bathroom I would think that it’s possible that they couldn’t come out, not wouldn’t. “
Reminds me of that wonderful Marx Brother’s scene in the tiny ocean-liner stateroom.