You are going to be a doctor. Unless you end up in a "no patient contact" area of medicine (and there arent' many of these anymore, even the radiologists are doing interventions and talking with patients now), you are going to have to introduce yourself to a stranger and make small talk to put them at ease.
In a med school interview, the interviewer should do this but you should be comfortable enough to be able to answer a couple of questions that are meant to loosen you up. (Is this your first visit to St. Louis? How are things up in Chicago; have you had much snow this year? )
Some interviewers are going to jump right to "tell me about yourself" so you should think (but don't memorize a script) about how you might describe yourself in 3 minutes. Think "well rounded" so be sure to mention not only your college, your major and your research & clinical experinece that has led you to apply to medical school, but mention things that are seemingly unrelated that you do to help you unwind such as athletics, performing arts, fine arts or crafts, (but leave out the things that you do to unwind that you wouldn't tell your grandmother about
).