You know, “hatch”. But it’s funnier saying door. Could a ship just dock with it, equalise pressure, and open the hatch? Or is there some sort of security? I tend to think there’s no lock because of a macabre situation where the crew are dead and the station is being recovered. But it’s amusing to think in space they don’t need to keep the doors locked.
On occasion they put a padlock on the inside. There was an incident where a guy was suicidal, because his lifetime project was cancelled while he was up there.