From what I've read, it is certain they'll ask about your reasons for going into medicine, and also for wanting to attend Upstate. I recommend you have really good and thoughtful answers for at least these 2. They seem to be guaranteed questions in Upstate interviews.
Another one that they seem to ask everywhere, specially the student interviewers is: what do you do for fun/ when you are not in class? I think the answer you give to this one will be very important to student interviewers, particularly.
In general, try to be conversational. From the moment you walk into your interviewer's office, try to talk about interesting things, and make them all come back to you and your app. As another poster mentioned, the interviewers don't know anything about you except your Upstate additional assays. They may not even know where you are from. I think this is good because you get to retell them your whole story the way you want to tell it. Concentrate on selling your best accomplishments and telling them how those have made you a better person and a better fit for a medical career/ Upstate student body.
Do all that in the most relaxed and cool manner you can, and you'll do great... I know, it is an art.
Hope that helps!
Ohh, almost forgot. During my interview, I was told to ask questions. That's how my interviewer conducted this particular interview. Prepare lots of questions but with the intention of tying them back to yourself and your app, otherwise the interviewer will answer but will not learn anything about you... that makes for bad interview reports!!