[After it's said, he almost feels better. There's nobody else in the world, in any world, who knows about what he's done. Joel stares her down with his chin held high, because needless to say it's not a decision he's willing to back down on. Despite his initial unease speaking about it.]

A Cordyceps mutation. That's what her immunity comes down to in the end. Marlene told me everything.

[He's amazed by how calm he sounds. Just run it by her, step by step. See how she takes it.]

Ellie was out when they first found us. They took her straight to surgery and they were gonna kill her right there, on the hope that they could whip up a vaccine from it.

[And there's that dark, quiet fury creeping over his words. Like he could snap necks all over again. There's a million reasons he could give as to why he thinks the Fireflies have always been short-sighted, but those excuses don't apply when he knows damn well what the most important reason behind his actions had been.]

And no, I didn't exactly cooperate.