The latest episode of Torchwood twisted the knife so much, it practically got a wrist cramp. All of the discussions about healthcare in previous episodes culminated in a scene of almost unbearable horror, laced with irony. All of the theoretical conversations turned horribly concrete.

Spoilers ahead...

This was sort of a classic Russell T. Davies setup, in which people eagerly participate in their own destruction by setting up bureaucracy and processes and officialdom. Some of the people in the system are fairly decent and well-meaning, like the soldier at the Welsh camp who nearly arrests Gwen. And some of them are basically scum who've been put in charge and are out of their depth, like Colin Maloney — who feels like a caricature, except that you're left with no doubt that people like him actually exist.

When living corpses are piling up, there's no wholesale solution that won't be horrific and inhumane — so inevitably the task of implementing a fix will be left to scumbags and people who are just following orders. People who have actual principles and a keen awareness of what's going on around them will be kept at a safe distance, or allowed to criticize from the sidelines.

It's the ultimate illustration of a basic truth about healthcare: Whenever you hear someone say that they're opposed to "rationing care," that person is full of it. Because we always ration care, and it's just a question of how we ration it, and who gets more or less. Healthcare is not an unlimited resource, and almost any disease can consume nearly limitless amounts of time and attention if you can pay for it.

In fact, on the face of it, a crude system of dividing sick people into the hopeless and the healing seems like a good idea. After all, in real life, we spend most of our healthcare dollars on the last few months of life — keeping people alive who are basically already dead. As Dr. Kevorkian would have told you, there are lots of people being kept alive even though they'll never get better and they'd rather be dead. There are wards full of brain-dead people who'll never wake up, there are heroic treatments being tried on patients who are just going to suffer a little longer.

So why not start dividing people into Category One, the people who ought to be dead, if we just let them — and Category Two, the people who are sick but can keep going? The healthcare system could save millions if we did that in real life.

The answer is, because people don't fit neatly into categories, as Dr. Juarez points out. Diseases are processes, not states. People progress from one state to another all the time. People move from Category One to Category Two, the way Rex did. And they also move from Category Two to Category One, like Gwen's dad. Nobody, not even the most clever doctor, can always predict what's going to happen to someone.

There's also the simple fact that stripping someone of their human rights — which is what putting them into Category One boils down to — is monstrous and horrible. (Although if you've ever had a relative stricken with Alzheimer's disease or some similar condition, you've already seen a person stripped of most of their human rights, in real life.)

Anyway, eventually we see where it all leads. Poor Dr. Vera Juarez, who took part in so many debates over how to handle the masses of people who were supposed to be dead in previous episodes — and now witnesses a final solution to the problem with her last moments of awareness. (At least, we hope that Vera isn't still aware after being burned to ashes. Because that would suck.)

Throughout this episode, the people who could be putting a stop to the dreadful machine are derailed by vanity instead. "The Categories of Life" exposes human vanity in the way that only a script by Jane Espenson could.

There's Gwen, who's started to believe her own hype and thinks she can just waltz in and get her father — her frail, deathly ill father — out of a giant camp full of soldiers and sick people. First she thinks that just showing up with the force of her steely personality plus the admittedly impressive sight of Sergeant Andy will do the trick. Then she goes all subterfuge, playing nurse dress-up. But she screws up, and it's her fault that her father suffers a second heart attack and slips into Category One — so her father's incineration is on her.

The scenes between Vera Juarez and Colin Maloney lurch from funny to sickening and back again. It's the collision of two vanities. Vera really believes she's better than all of this — even though she was part of the medical panels that helped make it all happen. She is sickened and disgusted and too proud to hide her feelings. Meanwhile, Colin is a small, pathetic man who's been promoted above his level of incompetence — but he clings to his delusions of adequacy. They're both full of themselves in such radically different, incompatible ways, that it's not really a surprise when he triple-murders her.

And then there's Oswald, who faces a stark choice in this episode. As Captain Jack points out, Oswald can only dance on the knife edge for so long. There are still plenty of people who want to crush him if they get the chance. Oswald will eventually fall from his protected place in the spotlight, just as every human being alive will eventually become a Category One if they all live forever.

So Oswald's choice is not between clinging to his fame or throwing it away — his only choice is how he wants to go. He can go quickly, by helping Jack to expose the truth and throwing away his Phicorp protection. (And in return, Jack promises he will help Oswald to die.) Or he can go slowly, holding on as long as possible. Watching the episode, I was genuinely not sure which path he would choose. The fact that he goes for the slow path is partly a rational choice — if he can stay on top long enough, maybe another way out will present itself. But mostly, it's a choice born of vanity. Oswald is discovering a weird gift for offering people the kind of balderdash they need at this particular moment, and he's becoming a pedophile rockstar in the process.

And it's sort of beautiful that we see Oswald's ludicrous pronouncement that this is a transformation akin to the leap from animals to humans 50,000 years ago, juxtaposed with the fate of Vera Juarez. Oswald insists that we're all becoming angels, at the exact moment that we see the fate that actually awaits all of humanity. We're all destined to burn.