Originally Posted by
bchandler02
Never seen a lock on a lav door that only locks from the outside. The times they have locked it, all they do is lift the cover and slide the same lock that you use from the inside. So, nothing to stop you from coming out if they did.
Op's lav door was blocked by the FA's seat if she didn't get up and move. It's a figurative "lock" because it's blocked. Not that they would use the door lock.