One thing that I can recommend from being on (non-admissions) interview committees for a couple of years is be personable. Your interviewers will probably interview around a dozen people in a day and you don't want to come off as awkward and robotic. Many times there was a potential coworker that looked good to me on paper but had zero personality. Those people got shoved to the back for the more enthusiastic and engaging folks immediately. It gets boring interviewing people that have memorized their answers to every question, so the ones that are polite and conversational can really stand out.
As far as the "about you" question, it's an opportunity to bring up personality traits, experiences and hobbies without it seeming too forced. It's really a license to take the conversation where you want it to go. So don't say "I grew up in X place, went to school at Y place and want to practice Z speciality." Try something more like, "I really enjoy X, have a dog/cat/parakeet, husband/wife/kid, etc. and throw in an interesting fact or experience." That makes you more human, and we want human doctors in medicine. And don't forget to ask your interviewers about their practices, interests, research or other topics. When I asked those questions they led to a lot of really cool discussions that helped me win them over. Good luck!