Here are some questions I've used:
1) How is the medical school planning to respond to..... (the rising numbers of the elderly, the uninsured/non-insured, global terrorism, you get the idea)
2) If you could describe the medical student body as a whole in one word what would that be?
3) What would the ideal class look like if all the diversity goals were reached?
4) If the particular interviewer wears many hats, you could ask what particular thing they enjoy doing most at this school (if they are happy, they'll go blabbing on forever...)
5) How do you think the medical curriculum will change in the coming months/years?
6) Any overseas opportunities, blah blah
7) how do you prevent physician burnout, blah blah
8) what does this medical school have/offer that others do not blah