I'm doing one with an old physician that I don't know and have never met -- he is my optometrician's (spelling..?) father, and he told me his dad used to do mocks back in the day...called him up and said he'd love to help me out. My opt. told me his dad does the mocks very uncomfortably, so it'll give me experience with the more rigid ones I may face. I'm doing another one with a physician I've worked with extensively who's a professor at a prominant med school, he'll probably be the more laid back interview.