“Midnight” is a self-contained episode that tells a complete story within 45 minutes. That story has physical and emotional consequences, both in terms of the story’s own thematic and narrative context and in the broader contexts of the then-current character arc and the overall framework of the show. It’s an episode that’s About Something, in the way all the best fiction (and Doctor Who) tends to be, and that thing is a perpetually relevant observation of human nature.

Granted, the observation is a cynical one that to some extent refutes the main character’s constant, defiant argument about humanity that would seem to define some aspect of the show’s infrastructure. It’s an episode in which the Doctor loses, for all of the reasons why the show usually allows him to win. This is an atypical episode for any number of reasons, be it the lack of companion (though the Doctor tries so desperately to find a surrogate one) or its incredibly limited physical scope. Yet in that, I think it’s hugely representative of what the show is, and is meant to be.

Doctor Who is basically an anthology series, like The Twilight Zone or The Outer Limits, except with a continuing central cast of characters and rarely the same strength of script. The Doctor is the Other, existing outside of each of these stories that he leaps into, and depending on the era he then sets about putting right whatever nightmare he has landed inside of, more to escape with his own life or to satisfy his curiosity or some other self-centered desire than out of any overt heroism.

Most of the problems that he stumbles into are dramas built of human pettiness, fear, and self-preservation. It’s not that he’s really all that much better than the best people in these scenarios; it’s just that he has an outsider’s perspective and a long lifetime of knowledge on his side. And indeed, much of the time everyone within the scenario resents his presence. Or his presence causes the problems in the first place. Or he imposes his own new order for his own reasons, but fails to stick around to see how tenable it might be. He tries to do good when it suits him, according to his own values — but it’s an incidental thing that he does on his way though.

Here we have an adventure where he is quite literally a tourist, in a place where (as with all of the supporting cast) by all rights he should not be. Things go wrong, as they do, and everyone is stuck within the smallest ever base under siege. I don’t mean the bus; I mean the head of everyone within it.

Historically, and even now, Doctor Who is a pretty cheap show. Words are cheaper than action; sets are cheaper than locations. For 26 years, but especially for its founding six, the show was written as an astoundingly well choreographed stage production. And so we have it here. We’ve got the Doctor, in a scenario representative of some aspect of life that the viewers will recognize, as an alien interloper — and all he’s got is a single set and the force of his character to go on. This situation calls for psychological horror, and that’s what we get — as we get at the best of times. Yet both unusually and appropriately here the horror is all from the premise rather than extra junk grafted on top. There are no physical monsters. Although there is a largely unexplained malevolent presence, it is as passive as a thing can be. All it does is reflect. Rather, the monster is in all of us.

Which, really, is what all of these stories are about. Even the overt monsters are manufactured representatives of some aspect of humanity or the human experience that has the capacity to trouble us. This is why facing those monsters can be so rewarding. Again, though, rarely in a Doctor Who story is the actual monster the Doctor’s greatest threat. Usually it’s the culture into which he has landed; it’s the very people who he attempts to help (again, mostly for his own ends) who stand in his way, put him before the overt monster’s face, and generally create the situation that has ensnared him.

Here we just get the raw version of that. Everyone is scared. He’s the outsider. Ergo, in their eyes he is the danger. Ergo, to him they are the danger. Yet they clearly all… well, most of them have such good to them as well. It’s not that these people are evil, or that evil is even a real thing within the context of this episode. It’s that they’re human, and they’re under duress, and they’re trying their best to deal with concepts beyond their understanding. And they do what people tend to do, at times like that.

In illustrating that dynamic, the episode gives relief to the basic message of Doctor Who — namely the glorification of curiosity; of asking the right questions, and trying to understand things beyond their surface. Here the people do earnestly try that, and the Doctor, being the mysterious central character — the eternal outsider — has to knock them away, and put himself forward as their agent of change. After he repeatedly refuses to account for himself, quite naturally they refute the imposition — and quite naturally, as the Other that he both is and sets himself up to be, he becomes their major object of suspicion. Again, and as usual.

By illustrating these dynamics, their ramifications, and thereby what they can easily mean in context, “Midnight” does more to illustrate what Doctor Who is about than nearly any other single episode. Just as the Doctor lends context by his outlier status, so “Midnight” does by its own.