Wow. Pretty cool catch. Better for me with the photographs than you with the camera, I'm thinking.
I know about the skinny door. Servant's entrance. When we bought the money pit we had three of them, two of which were right next to big doorways.
You didn't pay or feed your servants enough to make them fat obviously. We also had a set of servant's stair that went from just outside the kitchen to the servants quarters at an incredible angle. Couldn't have those pesky servants using our stairs, don't you know.
So. We closed them all off and took out the ladder grade stairs. One of the reasons we never put our house on the historic register. The people we sold to did but by then all the really stupid shit was covered up.
Are you serious? A servants door.., the house dates back to likely the 19th century when servants where commonplace here.. but.., that just isn't right!!
I didn't say it was right, I'm just telling you the answer :) I couldn't believe the duplication. Doors side by side. It irritated me, and I was really glad to see them go...
Our kitchen was just teeny too. No need for the help to move around much, either.
It was a good answer, I'm sure I have seen the once before somewhere.. in another explore but it's evading me.