Huh. I’ll be honest, the thought of arresting them then and there hadn’t even crossed my mind, but you do raise some decent points. They certainly seem to be as likely a suspect as any, what with Marty’s infiltration and Tayana’s open resentment toward and former history with the Vanguard. I’ll see if I can’t work something along those lines in.
Though, at that point, the MC is a single individual who has yet to even enroll in the Academy. They aren’t someone with the authority (or potentially even the skill) to bring Tayana’s crew in. So maybe not so much “You’re under arrest” as “Hey! Somebody come arrest these guys!”
Annnd now I know what I’m doing for the next half hour.