[TMWNN]

> A bunch of men from that day and age couldn't have figured out how to get out of that room? Or simply revolted and freaked out?

You're not thinking of this the right way. If a man had some health issue and needed to go to a hospital, or even if the men demanded to leave immediately, Morgan would have let them out. His locking the door was symbolic of his sense of urgency and determination to not leave the room without solving the crisis, something the others could tangibly see.