Okay that makes a bit more sense. Occlumency seems odd (like animagus) in that it still works when you are unconscious, I was assuming other more active types of mental defence,

It still strikes me as an odd tactic, though.

If I was trying to dominate someone I would knock them out, strip them, restrain them, gag them. Then wake them up. Make them powerless, not engage in an elaborate duel where they still have the agency to dodge and defend and may nurture the flame of hope of a lucky strike.