It is possible to get locked the wrong side of the final room of bm_c1a3a, where a scientist is waiting for you, to open the silo door and give you a shotgun. I don’t really get why this door needs to lock behind you at all, but if you start to go through it, then change your mind and come out, it can lock with the player on the wrong side at -667x, 620y, -63z.
Cheers.