Many people have their lives saved daily by surgeons who have learned the discipline of doing the unthinkable in order to accomplish the miraculous.
Ask a trauma patient, transplant patient, or the parents of a child undergoing open heart surgery.
Anesthesia and sterile drapes covering the usually unconscious patient certainly aids the surgeon in her duties. Health care providers go to work each day to help, not torture.
Perhaps the answer to the paradox is in the body of the essay(The Surgeon and the Torture Memos, NY Times, by Dr. Pauline Chen http://www.nytimes.com/2009/04/30/health/30chen.html): Dr. Chen describes the torturers as “seemingly ordinary professionals”…”not just a rogue group of military grunts.” It is difficult for Dr. Chen to imagine someone like herself committing tortuous acts, but not a “military grunt” (also a human being), which I interpret to mean a person who is not educated in a profession. Does less education equate to less humanity?
In my opinion, when we begin to differentiate humans into categories of “us/me” and “them/you”, we begin the processes of desensitization and habituation. This differentiation between categories of people allows us to find the justification to harm others, because “they are not like us.”
Sometimes, people commit acts so horrific that it appears they have chosen to no longer abide within the constraints of civilized society, and justice needs to be rendered. For that purpose, we have a legal system.