When you get to a certain point, Lucian summons you and tells you that you must kill everyone in the sanctuary.

I've been thinking.. If you didn't know better.. Wouldn't you think his sudden dismissal of all rules and everything you've been shown up to now, including killing other dark brothers and sisters..

Wouldn't you just stare and wonder.. If he is the betrayer and trying to cover his rear?

Maybe someone found out and is going to rat him out?

I was just thinking that.. The way it's done it points all fingers to him alone..