[reaperducer]

Houses of the past had this. Lots of old colonial homes have a small room with has doors to the outside and the inside that both lock.

Sometimes they're called "mud rooms" or "butler's pantries" or other things, depending on the age of the house, and the social status of the person it was built for.

That's why sometimes in old movies you'll hear the phrase "Tradesmen enter on the side."

[bambax]

Monasteries had gatehouses, which were an intermediary room between the outside world and the fenced inside.

Also, submarines.