Can anyone help me with a word I can't remember?!

[pyjamas89]

I'm trying to think of the word for when you have two doors into a place with a space in between (like a prison) - you have to close the first door behind you before you can open the second. I think another word for it is an airlock but that's not the one I'm thinking of. Google is just giving me riddles about prisons and doors and guards! Does anyone know what I mean?!

Like an anti chamber? Vestibule?

*Antechamber

Vestibule? Lobby?

Google for me suggests mantrap, air lock, sally port of access control vestibule

Just googled it and it seems to be called a mantrap, aka air lock, aka sally port, aka access control vestibule. Any of those what you’re looking for??

Yes @icedaisy! It's sally port I was trying to think of
thank you all for answering my bizarre plea!

Ah icedaisy found the same link as me but quicker! 😄

@Notname cross posted,thank you !