When Lucifer rose in that convent in Maryland, Sam knew Dean wanted him dead. He knew it at the very core of his being, felt it in the bile churning in his gut. But it didn't stop Sam from grabbing for Dean as the light grew to blinding. He felt Dean grab him back, and briefly wondered if he was about to be throttled before Lucifer was even top-side. But no, Dean was dragging him to the door, trying to get them out. Because of course Sam couldn't be let off that easy.
But then the two were sitting on a plane, Sam still curling up halfway into Dean's space like he deserves to be protected, and Dean couldn't exactly kill him with more than a hundred witnesses. Still, Sam couldn't breathe easy. Especially when the plane starts to go down. Sam tries to fight back the terror, because this is another chance at an easy way out for him. But he can't, because Dean doesn't deserve to die. Not like this, from the one thing in the world that terrifies him.
Dean didn't kill him when they landed, because he's still shaken up. He doesn't kill him when they get into the rental car, because they need to figure out what's going on.
Because that has to be it, doesn't it? Dean wouldn't just draw this out to hurt Sam. Or maybe that consideration had gone out the window when Sam had raised the devil.
Tired of the silence and the tension that fills it, Sam finally starts to say something, but Dean stops him. He says it's okay, which it isn't, and that they need to keep their heads down and hash this out. Which makes sense. Sam should have to stick around to clean up his mess, even though he wants to cry at the idea of dragging this out.
Or maybe this is the plan. Maybe Dean will pretend that things are fine and then blow Sam's brains out when he least expects it. That's preferable, Sam thinks, and hopes his brother doesn't make him suffer for long. He ignores the stab of guilt he feels at his desire for mercy, and shoves it down. It's nothing compared to the guilt of putting Dean in this position.
They find Chuck, and they hear his horrifying analogy for how Castiel was blown apart, and Sam has never wanted to die more. He feels the biting guilt rise again, and as much as he wants to, he doesn't try to numb it with alcohol, because he deserves to feel it.
And even though it's the apocalypse, Sam is only half-aware of everything that's happening. It feels like he's underwater, senses dulled to the chaos of the outside world. He tries to focus as the days turn into weeks, as Dean still refuses to either talk to him or kill him. But while Sam's body is solidly on earth, his mind is in a hell of his own making. Time starts to pass in flashes.
Night after night, he wakes up gasping from night terrors. Dean is always awake; Sam can tell from the steady breathing he uses to ground himself. He says nothing, every night, as Sam tries to pretend he isn't fighting for breath.
For the first time in their lives, Dean doesn't hover over Sam. He doesn't make sure he's eating, or sleeping – and he's not. There's no joking anymore, no reprieves from the horror their lives have become. Occasionally, Dean's control slips, and Sam will see the hatred in his eyes. Hell, sometimes Dean will blurt out some jab about demon blood or lying or betrayal, only to brush it off and pretend everything's fine when Sam jumps on the chance to talk about it.
Dean keeps the weapons out of Sam's sight whenever they're in the motel. No more casually cleaning guns and sharpening knives, even though Sam knows it soothes his brother. He wants to ask why, but knows it will go nowhere. Sam can only assume Dean doesn't want him to see it coming.
Sam knows he deserves it, but all the little things, the mind games, start to add up until he wishes that death by a thousand cuts was a viable option.
Bobby cuts Sam out of his life, and Sam knows he deserves that too, but damn it hurts. So he stupidly leaves Dean to be attacked by the demon inhabiting Bobby, and Bobby ends up stabbed for his trouble. Even if it was a demon talking, it was right. Bobby would've been so much better off if Sam wasn't in his life.
As Bobby lies fighting for his life in the hospital, Sam realizes he was wrong. This is the moment when he most wants to die.
Cas miraculously returns to rescue them in the nick of time, and Sam wishes he had let him die. Having his lungs ripped from his chest was less painful than what he's living.
That night, he's had enough. Sam waits for Dean to fall asleep before slowly climbing to his feet. He knows Dean has his gun under his pillow, but even if he could get to it without Dean waking, Sam would never take his brother's favorite gun. Not for this. Instead, he grabs the Impala keys, sneaks towards the door and starts to crack it open. No reaction from Dean, so Sam slips out the door and heads to the trunk. He picks up the first gun he finds, loads it without thinking, places it to his chin. He's taking a deep breath to steel himself when he hears the footsteps.
"Going to meet another demon buddy?"
Sam's back is to Dean, so his brother can't see the tears that prick at his eyes. Dean's tone is full of hurt and anger, and Sam starts to wonder if this is the moment. Dean had said they had to take down Lucifer first, but maybe this is the straw that breaks the camel's back.
"Please go back inside, Dean." Sam's voice is barely a whisper, and there's a beat of silence. Sam keeps the gun pressed against his skin. Dean can't see what he's doing from this angle, but if either of them moves, he'll surely notice the gun in his hand.
"Sam?" Dean asks, hesitant. His tone has changed, as if he's talking to a spooked animal, and Sam knows he knows. Somehow, he knows.
"I'm sorry," Sam murmurs, because he has to. He can't do this without letting Dean know how sorry he is. It costs him a second of focus, and Dean lunges for him. Sam tries to struggle, but even if he had any fight left in him, he won't hurt Dean. Not again. So Dean easily disarms him and guides them both to the ground. When he looks down at the gun he's just taken from Sam, a sharp breath punches out of Dean's chest. Sam starts to try to grab the gun back, but stops at the look on his brother's face.
"Sammy," Dean whispers. "Tell me you weren't doing what I think you were." He tucks the gun into his waistband and grabs Sam by the shoulders, trying to meet his eyes.
"I'm sorry," Sam says again, tears falling freely now. "I should have let you do it, but I can't take it anymore. I'm not strong enough."
"You should have let me what?" Dean asks. He locks eyes with Sam, and for once, Sam can't find any hatred or disgust, just fear. The look on his face is practically begging Sam not to say it.
"Kill me." The words ring out in the dead of night like the gunshot that almost was.
For once, no words come to Dean immediately.
"Like you said," Sam prompts, as if Dean needs a reminder. Dean still stares at him, horrified, confused. Sam reaches for his pocket to grab his phone, and Dean flinches as if Sam has another weapon on him. Sam pulls up the voicemail and puts it on speaker. He's numb to it by now, even though he's only listened to it once. It was all he needed for his memory to echo it constantly. He watches as a wave of rage and disbelief washes over his brother. He's still holding Sam by the shoulders, and his grip tightens in desperation.
"I am never going to kill you," Dean says, voice shaking. "And I never said that."
"Dean, you heard the-"
"The angels must have fucked with it, Sam, because I said-" Dean chokes on the words a bit, the words Sam never got to hear. "I said we were still brothers. And I'm sorry. Fuck, Sammy, I'm so sorry."
If Sam had been floating underwater for weeks, sinking to the bottom, he suddenly snaps to the surface, gasping for air. Everything that had been dulled snaps into sharp contrast. The cold concrete underneath him, Dean's shaking hands holding onto him for dear life, the reality of what he almost just did due to some angel bullshit.
"You kept the guns away from me," Sam says, less an accusation than a realization.
"Because I was afraid something like this would happen." Tears are falling down Dean's face now, and for once he doesn't seem to give a shit. He's giving Sam this look that screams oh my god I almost just lost you, and Sam almost flinches away under the intensity of his stare. "I should've just talked to you if I even thought it was a possibility, Sam, fuck. I'm so fucking sorry. I knew you weren't okay, and I shouldn't have ignored it because I was too caught up in my own shit."
"I started the apocalypse, Dean." The words are still bitter on Sam's tongue. Maybe they always will be.
"So what, you should kill yourself? Yeah, Sam, you really screwed up, and I'm pissed about it. But you're my brother." The way Dean says "you're my brother," the way he always has, makes it clear. It says all the things Dean can't find a way to put words to, and Sam suddenly knows, in his heart of hearts, that they're in this together, even after everything.
Then Sam is the one choking back a sob. Dean pulls him into a fierce hug, and time stops as they cry for themselves and each other. For what they've lost, and what they haven't.
For the simple fact that they'll both be here to see tomorrow, together.