It didn't matter how it had happened—not really.
He wasn't even his Spock, technically speaking, but as Jim sat there in sickbay watching him die, a vague, borrowed memory was brought to life. He was watching Spock through the glass of the radiation chamber putting his hand up in a Vulcan salute, and returning a Vulcan kiss.
He hadn't understood—he couldn't have understood—when Spock gave him the memory. His mind couldn't make sense of the data he had received in that transfer, but now it could. Jim could suddenly understand what he had been feeling, in that other timeline, and what Spock must have been feeling when he'd purposely switched their roles.
It was selfish, he realized when he thought about it. Selfish to sacrifice himself and leave Spock to mourn for him. The half-Vulcan was strong in defense of those he cared about, but not in defense of himself.
And he wasn't even his Spock, but tears were sliding down Jim's cheeks for this, for the first time, for the last time, for the pain he'd caused, for the pain he felt. He had reached forward to grab the hand of his unlikely friend before he could remember why he shouldn't. He moved to let go, but Spock didn't let him. Instead he gripped Jim's hand with a startling strength.
He couldn't speak, but he initiated a meld through their entwined hands. You and I have watched each other die before, my friend, he said, Spare me the heartbreak in your eyes this time.
Jim cursed himself for being selfish again. It seemed he would always be selfish, when it came to Spock. He forced his features to relax, and even managed a weak smile. He heard soft laughter in his head.
You are being illogical. Go. Do not mourn for me here. Be with me.
An image of the other Spock, his Spock, passed before Jim's eyes. He was wearing an expression Jim had never seen on him before. He was almost smiling. And suddenly, Jim understood.
A real smile broke through, and suddenly he was all but running out of sickbay and through the mostly-empty halls.
Spock opened the door almost immediately, and silently beckoned him inside.
It was almost funny. Jim had spent so many of the past 48 hours trying to find a way to tell Spock that he was dead. He had written himself script after script in the long hours he'd spent in sickbay.
But when the door shut behind them, he said nothing. He threw his arms around Spock's neck. The Vulcan was at first too surprised to push him away, too surprised to move. Jim allowed himself to feel all the love he had for Spock, and all the pain at his passing, without holding any of it back.
Slowly, he felt warm arms wrap around his waist, holding him tightly against his t'hy'la's chest.
Jim didn't know when he'd started crying, choking on tears, or when Spock had begun weeping silently into his neck, but it didn't matter.
It was enough.