The thing about broken hearts, is that John's was already broken.

Or breaking, anyway, if not yet broken past the point of adequate function.

It turns out that EOS was a stopgap, versus the sum total of things that would have killed John eventually, anyway.

It turns out that nearly three years spent in a physically demanding, unnatural environment, doing an intensely high-pressure job, stepping around the actual process of grieving a lost father, and instead stepping up to meet the extraordinary needs of an extraordinary family—it turns out that would take a certain toll on anyone's heart.

It turns out that being targeted, singled out and ravaged by a forgotten, supposed-to-be-eradicated disease—having parasites tear through one's blood and one's brain and demand a rallied defense from a weakened and dormant immune system—that's the kind of thing that takes more than just two weeks of aggressive chloroquine treatment to recover from.

It turns out that, more even than pushing the limits of one's health, being subjected to the mental and emotional strain of trying and failing to make the case for a fundamental belief—trying and failing to save a life that no one believes actually is a life—is the sort of thing that turns a person to desperation, nearly to despair. The sort of thing turns them away from their family and outward, alone into the world, in pursuit of the only possible person who might have been able to help, even if that person is supposed to be a dead man.

And it turns out that allowing three dubiously credentialed thugs in an anonymous back room to cut open one's chest and insert a pacemaker; to thread leads through one's arteries and into the heart—is the sort of choice that results in a build up of scar tissue in atrium and ventricle, in slowly blossoming infection, and a breakdown of essential functions, and it poisons one's heart from the inside out.

And maybe EOS' presence was killing him, but it's in the immediacy of her absence that he's dying. And though John's is the sort of mind that's always had a good grasp of causality, in a state like this, it's hard to tell the difference between being killed and just dying. And between dying and wanting to die.

The truth is that it's finally too much. For so many reasons—reasons of exhaustion and ill health and trauma and just basic, binary function—John's just not capable of sustaining this kind of grief; the immediacy of this loss. Even as her last words ring in his ears, and he knows them for the last thing he'll ever hear her say; John's heart is what fails him. Stress and adrenaline and the exertion of high emotion send his heartbeat rocketing into a state of tachycardia. The fall of darkness is sudden as always, but for the first time, it's not unwelcome. If there's any fractured part of him left still capable of hope; then John hopes that it lasts beyond the bounds of his ability to feel.

If he'd woken in his father's arms, then he would have died. If his father had been the one to come for him, then it would only have been right; would only have been fair—for his father to feel a fraction of the loss he's caused his son. For Jeff to have to beg and plead with him, at the edge of his own oblivion, on the cusp of following his own reason for existence into the dark—

It would have just been right. And if John's heart has broken, then it's not the only part of him that's done so; and he'd have denied his father, and given up, then and there, to teach Jefferson Tracy a lesson that he should've learned, long, long ago. If it had been his father, John would have let go of the edge, and fallen off into the dark, and gone where he wasn't supposed to follow.

But it's not his father, because it's Alan.

Because in the end, it's always Alan. If John's in trouble, then it's going to be Alan who comes. That's Alan's job, after all.

The part of his brain responsible for causality doesn't question why Alan's here; how Alan even can be here. There's nothing about Alan's presence that doesn't make sense, because somehow Alan's always seemed to know when John needs help, and what to do about it. Certainly better than John ever has. How he'd known where to find his brother isn't even that difficult a question, because John's just where he always is; where he's supposed to be—aboard Thunderbird Five.

Or, it looks like Thunderbird Five, anyway. Something about that conclusion seems wrong, but he can't quite seem to pull his thoughts together enough to determine just what.

Maybe Alan can help.

Maybe Alan will know what to do about the crushing, unbearable pain in the center of his chest; the pressure that seems to be squeezing the air from his lungs, that leaves him with nothing left to put towards words, if he even had any idea of what he's supposed to say.

Alan's pulled him up off the floor, away from the curving arc of the gravity ring. Alan's got an arm wrapped around John's back and a hand clenched against his his shoulder. Alan's eyes are wet and his nose is red and his fingertips are fumbling at the side of John's helmet, the left side, near his jaw, where the external controls for his radio are. There's a hiss and a crackle of static, a soft whine of feedback as Alan gets them both on the same frequency.

"—ohn? Can you hear me? Just hold on, John. You've gotta hang on a little longer for me, okay?"

He doesn't want to. Even if it is Alan asking, John wants to ask why he should, or how he's supposed to, or what could possibly left for him to hold on to. There's numbness spreading to his fingertips, down from his left shoulder and across to his collarbone, tightening sharply across his chest. Everything hurts and he's so desperately tired; he feels hollowed out and weighed down all at once, and the oxygen he can't spare for words isn't quite making it to his brain, either. He doesn't understand what's happening, only that it's the worst thing that's happened to him in his entire life.

The edges of that thought represent a agonizing reality, and the truth of it is sharp enough to start to sever the ties that are keeping him here, biting keen and sharp and painful, trying to cut him free.

But, it's Alan.

And Alan's here and Alan's real and Alan's got tears streaking the inside of his helmet's faceplate, and John can feel his little brother's hand gripping his shoulder, even through the numbness, something holding on to him. There's a knock of perspex against perspex, and when John blinks his eyes open again, he realizes his little brother's bowed his head, pulled him closer than before. There's still a comm channel between them, but it feels like Alan's voice is right in his ear, tearful as he says, "Johnny, please. C'mon, I-I told her you weren't gonna die. John, let's go home. Just come home, John, please, I just want you to come home. Please, stay with me. Please, please, don't go."

There's something weirdly familiar about the things Alan's saying. It's almost like he's said them before, though John can't remember when or where. They seem like the sorts of thing John's said himself, not all that long ago, though he's fading out and it's hard to remember anything. Especially when some deep part of him knows he doesn't want to; that all he wants to do is let go, fall away, and forget.

Still. It's Alan. And his voice sparks off something in the depths of John's soul, reminds him of something he'd all but forgotten. So though it costs an enormous amount of effort, far more than it should, John manages to lift a hand to clasp his little brother's shoulder, just before everything falls away again.

If there's a line between John Tracy, death and dying, it might just be that Alan's it.