"So when I heal people I see their memories," Magnus says. Usually he doesn't share people's memories with anyone else but he's already told Claudius about this one when everyone at the Mansion except Magnus got truth-spelled, so it's probably fine, right? "I can't not. That's not the secret, everybody knows that. But when Enjolras got here, he was like, full of bullet holes? So obviously I healed him, so obviously I saw his most important memories at the time. And the biggest, shiniest, most important one? Was of Grantaire holding his hand."