something tells me he's the leader because he's seemingly calmer than the other being walked to the police car (who's visibly sweating out of anxiousness)

He's sweating because he's not a part of the cult. He got ambushed and forced into the robes at the last second.
Notice that during the initiation, only two cloaked figures have glowy eyes - the woman and the leader. The eyes are their spectacles reflecting light. The other two cult members don't wear glasses and seem to have escaped the police, one by forcing his robe on the poor bespectacled guy being arrested.