I managed to entomb a dupe in a unpowered mechanized airlock...
I noticed that in DLC mechanized airlock are a bit.. weird, as in "dupes stay in one side of the airlock door while finishing jobs in the other side" or "dupes stay for a couple of seconds deep in thought in one side of the closed door waiting for it to open again"
How this specific entombed dupe happened:
I finished my last playing session here
Space Hut 315.sav
before digging/building the ladd
Branch: Live Branch