Kell does everything that Kyle tells him to. He takes the berries, and the coat with gratitude. Hunger is significantly less of a problem than it was in their captivity, but the cold took its place. It's the kind of cold he has never experienced. Having been snatched from the street with only the clothes he had on his back, he was unprepared for it. It's a creepy, insidious kind of cold. One that sneaks up on you the moment you stop moving.

The warmth of Kyle's coat melts away some of the iron resolve that Kell has been holding on to by sheer force of will, and he staggers. Suddenly, he feels dizzy again. He's been away from the camp for too long, didn't even realized how much the cold was able to get to him, his strength slowly seeping out with each step of this trek.

Lucifer's words snap him back into focus, draws his gaze from Kyle to Lucifer.

"Good," he says. "They will need both numbers and competence."

Kell hesitates. It would have been so easy to say nothing; just let guilt slowly gnaw at him. At least he'd avoid Lucifer's inevitable rage when he learns what Kell did. What he let Istredd make him do. But he also knows that if this was him, he would want to know, and it's both cruel and cowardly to stay silent.
Kell looks away before he finally musters the courage to speak. He must say what has to, but can't look Lucifer in the eye while admits that he just left Istredd to whatever fate the Acolyte planned for them. Fully aware they could, and probably would, retaliate on those that stayed.

"Istredd is still there. He helped us escape, but he didn't make it out himself."

Each word dripping guilt like blood. And I left him. Kell doesn't say that. As he doesn't say that Istredd practically kicked him out, made him promise he'd drag Wilhelm and Mat out. He did that. So, in theory, he shouldn't feel so rotten now.