Well, he tossed a barrage of questions at me because I hadn't had any experience in a dental clinic.
He basically implied that I have no idea what I'm getting into, and that my interview space would be better off going to someone else. Further, he was trying to convince me that I wouldn't enjoy dentistry and that my lack of research into the field would be my inevitable downfall.
Now, I didn't even realize what his purpose was, I felt he was singling me out. So I let him do the talking, and interjected when I could about how certain I was to join the ranks of the dentists. I didn't really panic, I was shocked that he'd be the way he was, after having gone through a really good interview at BUSDM.
In my most humble opinion, I feel the best way to handle it is to take the questions, and think about them. Don't get defensive, and don't cry to yourself about them. *If* he points out something you didn't know, acknowledge it and then address it as best as you can. But show your conviction, and your drive.
I had managed to convince myself that I had messed up the interview, and that I'd be rejected right off the bat. A week later I was accepted. *shrug* I still don't know what the right answers were and in fact, I can hardly remember the interview at all.
Good luck, and let us know how it goes!
Dante.