Is there even such a word?
EDIT FOR USAGE CLARIFICATION: The image I have in my head is of the lead character in Prison Break smacking his face into the bars of his cell until it bled so he could get his cellmate put in 'the hole'. This was to further a much larger scheme.
EDIT MARK II: Upon further thought, I think I may actually have meant to say "person with no taboos in their psyche." They'd have no distasteful response to any action if it furthered their aims.