"Sam?" Marcus asks, then shakes his head. "No, this wasn't planned, not as far as I know. Dan came into the room after you and he said it might be the only way for me to properly speak with either of you."

Not a way to say goodbye. Dan had been very clear on that, he wasn't doing this so Marcus to properly communicate to Kat just how much she's come to mean to him and he won't disrespect Dan or his trust in Kat and Sam by doing so now. Even if he wants to. Even if he's desperate for her to understand, just in case.

Instead, he says, "It's called Vetis. Tempter of the holy. Sam needs to know its name and he... if he makes it angry, if you make it angry, it'll be easier to banish. I think it might hate you a little bit more."