I’ve seen a down-size real-estate development (aimed at the retired), where the double-door full-bathroom opened to the master bedroom on one side, and the kitchen on the other. In context, it had an obvious advantage for someone with reduced mobility.
Dr Semicondutor!
He’s turned his shed into a positive-air-pressure class-100 clean room, with HEPA ventilation and air-lock gowning area.
A house I had in Florida had the shower in the middle…between TWO toilets.
I’m not sure what you are describing. Was that bathroom cut into more than one room? The only Jack and Jill bathrooms I’ve ever seen had a sink, toilet, and tub. The tub might have also had a shower, or not.
Actually, I have seen what @nearwildheaven described, in a college dorm room. In my dorm room there was a sink for the use of my roommate and I, and then a door leading to a room with a shower and toilet, followed by a door leading to the adjoining room. That room presumably had its own sink.
For a short time my family rented about half of a huge house that had been added-on-to over many years but the entire structure was completed pre-Revolutionary War. (Lots of changes since, mostly extra bedrooms split up to provide bathrooms and some sort of “extra” space like library nooks and mini-sitting areas.
Anyway, the result included lots of relatively strange features, like a hallway that led to nowhere at all, and a staircase that went up only to end in a small closet, and a dining room that was basically on the other side of the house from the current kitchen. One strange feature was it had, um, double sided closets? between most of the bedrooms. A normal looking closet, usual depth and width with a single hanging rod down the middle, but doors led from the closet on both sides into otherwise separate bedrooms. Made very handy escape routes when playing hide and seek type games.
So did you check if one of those closets led to Narnia?
One bedroom was the owner. The other was for single houseguests of their preferred gender
In my aunt’s old house (designed by her husband), the main bathroom has two parts: There’s an open doorway without a door to an area with a couple of sinks, and then past that there’s a door to the room where the toilet and shower are. Convenient: You don’t need privacy while you’re washing your hands, and this lets people do things like washing hands (or brushing teeth or whatever) while others are in the private room.
My grandma’s house had that between two of the rooms, though they were side-by-side, not inline, and it was a slightly tight squeeze. And yes, we kids loved that there was a “secret passage”.
Was the owner’s name Winchester?
A friend of mine had his game room set up to look like a D&D dungeon, with the walls painted to look like stone, and of course a table, chairs, and a mini-fridge. A couple cheap weapons and a shield on the walls added to the decor.
It was actually cool and useful.
A medieval mini-fridge, of course, right?
Sadly, no, but it was painted. Sconces on the walls looked somewhat like torches.
My first apartment out of college had a bathroom with two doors, one to the master bedroom (2BR apartment) and the other opened into the entryway, with the kitchen on the other side.
LOL, I’m pretty sure we didn’t characterize it that way when we went to sell it. Maybe “bonus storage room”. I don’t really remember now.
But it was a very handy gift wrap room, too. All those countertops made cutting lengths of wrapping paper a breeze.
Really, I have two acquaintances who have rooms they call and use as “dressing” rooms, and I already find that a little decadent, but a gift wrapping room? 
What can I say? I like to give people nicely wrapped gifts! 
Maybe it’s because I’ve never learned that special art. I wrap gifts like the engineer that I am. Practical, without unnecessary pomp. 
A regular table, wrapping paper, scissors and scotch tape are sufficient.
My grandparents had that in the church manse, Illinois. I was 3. I’ve wanted it ever since. The function was that they stored their winter coats in the middle of the very deep closet. And it had two doors, because when you make a closet that deep, eventually it’s going to run into another wall anyway.
When you’re 3, you can crawl under the coats from one end to the other.
Of course, it’s still possible that they built two duplicate houses, one here and the other in Narnia. Did you ever go through to the other room in two different ways, and notice that it was slightly different?