How do the Doctor and his Companions take care of their basic biological needs while they’re traveling in the TARDIS? It’s a question perhaps less pressing when considering Clara than most others, as she seems to spend little time at all there. We’ve seen her changing clothes after an adventure, but on-screen evidence suggests (to me, at least) that she rarely, if ever, so much as spends one night aboard.

Even as recently as Rory and Amy, though—another pair who treated their time on the TARDIS more like a commuter than a residential lifestyle—it was clear that long stretches of time passed between their visits home. Historically, Companions lived in the TARDIS more like a dormitory or a commune, presumably spending their time between adventures in its halls.

So where do they sleep? Eat? Relieve themselves?

I suppose one obvious answer is that they stop off at various planets (or space stations, or whatever) to get supplies, have a picnic, or find a place to crash. (After all, Rose and Nine talked in The Empty Child about needing to stop for milk: “All the species in all the universe, and it has to come out of a cow,” he quips.) It makes a certain amount of sense that part of exploring the universe is exploring various species’ cuisines, for example.

I don’t think that’s how it works, though. We saw early on (in The Daleks, the second-ever story to be broadcast) that the TARDIS was equipped with a food machine that could produce (rather unappetizing looking) blocks of nutritional matter, programmed to taste like whatever one liked. Although it barely ever showed up again, that seeded the idea that the crew had everything they needed without ever leaving the ship.

Further, we know for a fact that several Companions have had regular bedrooms. Barbara and Vicki seemed to share sleeping quarters (with what look to me to be painfully uncomfortable chair/bed hybrids). We’ve also seen rooms that clearly belonged to Romana II, Adric, Tegan, Turlough, and Nyssa as well as a couple that were decorated as bedrooms, but not specifically assigned to anyone (including the one in which Peri wakes up in Planet of Fire—which may eventually have become hers). And although we never saw them, we know Amy and Rory had bunk beds in their room.

Generally speaking, we’ve seen less and less of the TARDIS’s interior as time progresses, though there are two stories in particular that buck that trend. In The Invasion of Time, the Doctor and Leela traipse all over the place, including random corridors, an art gallery, and—most famously—a swimming pool. It was the first time we really got a feel for the TARDIS’s inner dimensions.

The pool is referenced when the Doctor falls into it in The Eleventh Hour, but doesn’t make an actual appearance again until in the second story to showcase the ship’s interior: Journey to the Centre of the TARDIS. As Clara wanders around, we get a better sense of how vast the TARDIS’s interior really is—especially since it includes an observatory, a massive library (~drool~), and an equally massive storage room full of the Doctor’s memorabilia.

It all makes it that much easier to believe that she’s got plenty of bedrooms and a kitchen in there somewhere. And toilets.

People don’t like to think about washrooms, especially not in our fiction, but who can honestly say they’ve never had any sort of mental breakthrough—a different perspective on a problem, a new idea, or a fresh insight—while taking care of business? It’s not glamorous (which is probably why it never happens that way in fiction), but it’s pretty common.

When I envision the TARDIS bathrooms, then, I imagine them being scattered at regular intervals throughout the area that serves as living quarters. I also think that only those in active use are actually fully configured. When someone walks into one of these rooms, depending on mood and need of the moment (toilet, sink, bath, etc.), the washroom adapts itself to suit.

Perhaps it’s an entirely utilitarian visit, and the individual just wants to be done and gone: a simple, spartan half-bath coalesces. Alternatively, maybe the occupant feels the need for a more meditative state: there’s the high-end granite and tile surroundings to give just the right touch. And as for bathing, it could run the gamut from stark, walk-in shower to luxurious, king-sized tub.

I love the idea of the TARDIS being in tune with her crew, caring for their basic needs so smoothly that they never even think about it until they need to go back to a life without her again. It’s my new headcanon. Because of her love for the Doctor (I don’t think that’s overstating their relationship) and his love for his friends, the TARDIS makes them feel at home. It’s her way of showing him she cares.

But I wonder if she ever short-sheets Clara’s bed.