Perfect superwho :) (or what if Crowley started possessing him after the events of The Impossible Astronaut? Either that or the sonic just doesn't have a demon setting) <-- that'd explain how easy it was for Canton to accept the silence.
But can you imagine Moriarty running into Crowley? I mean, Moriarty is scary and psycho, but he's human. Crowley could destroy him with a snap of his fingers. Basically I'm saying I would love to see Moriarty shaking in his boots before Crowley 😈