Most of my interviews focused on why I wanted to go into medicine after a mechanical engineering degree and almost 9 years as an engineer.
Aside from that, my first interviewer opened with "Tell me some things about yourself that aren't on your application." You try so hard to put all your relevant information on the application that it was surprisingly tough to answer.
I also got, "What are you most proud of?", "What was the most difficult thing you've done?", and "What would you do differently?" The second interview was much more conversational.
For some more general thoughts - the admissions staff was pretty casually dressed, with everyone in green polo shirts. Of the 5 people who interviewed on my day, two girls were in suits, one was in pants + blazer, and the two guys were in dress pants/shirt/tie getups. I would suggest a suit, but it doesn't have to be hardcore.
Also, if they give you a time frame for check-in, keep in mind that there is nothing to do during that window. You could check in right at the start and then wander and chat with other applicants a bit, or check in towards the end of the window. Just remember they usually have ~60 people interviewing per day.
If you haven't met Jennifer, she's much younger than most people would expect for an admissions director (late 20's/early 30's?), and she'll be dressed like the rest of the admissions staff. Makes it all the more important to be nice to everybody you meet.