"No." That's about when Poe realizes that Jyn has no idea about the difference in their timelines. His eyes widen, for a second, but he manages what is (for him) a quick recovery. "Finn...."

Poe stops, realizing also that in telling them about his friend, he'll be admitting to more of what happened to him before this place.

It's all in a report somewhere, Poe thinks, jamming his fingers into his hair and ruffling it. Just get it over with.

"He was a stormtrooper. Turned on them during his first battle. Couldn't--" The screaming. "Couldn't kill civilians. He broke me out of the belly of a Resurgent-class Battlecruiser."

He frowns then, looking first at Cassian then at Jyn. "He's a good man."