In terms of Preventer, their whole armory can do serious damage but the weapons don't kill since Bruce had them swear to be non-lethal and shiznit. The Mass Effect crew can help themselves! Right now, Preventer is more like an "insider" organization. They have good political relations with ship authority but are actually undermining them for within. 8) Ship authority knows they have an anti-Purist agenda but can't exactly outright tell Preventer "Hey, stop that! That's us!" so it's a delicate situation. They're limited in what they can do outright but hellz yeah, they will help sneak around.