What would cause an otherwise very confident and powerful person to ENJOY being !

I dated a guy in a very high position of authority. He was wealthy, charming, wonderful. everything a person would want. But he wanted to be tortured. I felt uncomfortable because I felt like he was doing it out of some inner guilt. We broke up. Years later, we are still friends. He recently confessed to me that the reason he likes to give up control is because he always had to be in control in his work life, so giving it up was a huge relief for him.

I would get him to go running or something else that is extremely active...maybe he just needs a burst of adrenaline in his system. It could be a brain issue or something like the need to feel controlled, which could be helped with counseling. If he begs you to do it....don't. If he persists leave where he is. Doing it any way is not helping him, it is only counter productive. It sounds like he could benefit from meds, counseling or both. Once this is no longer giving him the "feeling" he needs, he will find something else that could be even more destructive and dangerous.
He really is control of his own life, you cannot make him do anything. But, as a friend you can encourage him to get help or make it a condition of your friendship. Good luck. People are all different. But, if you do what he asks and you seriously hurt him, you will never forgive yourself. Also, just a though he is actually controlling YOU by begging you until do what he asks. He may be enjoying "getting his way" with making you do something you clearly don't want to do. Just some various thoughts.

You should get uninvolved really, really, really fast! What makes you think he's not going to eventually enjoy beating the crap out of you?