also he knows he can't be the one to make that call for Asscreed World. Because he's from the farthest in the past so he knows it has to survive after his time to at least Desmond's.
He's made the mistake of letting her run off to do her own thing before... And while it grates on him to have to grab her, he knows she'll make him regret it if he doesn't
and possibly carry her back kicking and screaming