Two scenarios for the Specialist:
1) Can he use his Shotgun twice (once with a Charge, second time by flipping it) for the same action?
2) Can he use his shotgun once by flipping it, then unflip it using his card-back special ability, and use the shotgun again, all to pay for the same action? In this case, the Unflip action would be made as part of the Intent Payment phase for the parent action, but instead of generating any Intent itself, it would activate a new Intent source.
1)I play it this way. I even discard multiple Charges and sum the intent up.
2) I think not. The Unflip is a different action and I think that an action has to be completed before you take a new one.