And there is always the "rogue splinter group" way of doing things. IE the black ops type group that doesn't mind doing the really dirty things as long as it's for a good cause in the long run, but if they're ever caught, the main Thorvengers group will, to steal from Mission Impossible here, disavow any knowledge of their actions. No paper trails that can be traced back to the main group, stuff like this. I can see renegade Sheploo volunteering for this, probably someone like Thane too, etc etc.