As your interview wraps up, your interviewers will ask if you have any questions. You must have them. Being interested and thoughtful demonstrates your commitment to the program.
With student interviewers, your questions can be more personal, but you still want to show that you know something about the school. It's also a good idea to ask a question that relates to something you've just discussed or about a commonality that you two share, or that you share with the school:
You mentioned that you're involved in researching X. I, too, have a background in researching X. Or, if you’re into completely different areas of research: I’m very interested in pursuing research at Specific Lab. Can you tell me more about your work at Specific Lab?
My grandfather was in the Army, and I value our veterans. I know that the medical school has partnered with the local VA center to address both chronic pain and mental health issues. Have you worked there? What is it like?
I’ve read about X, Y, and Z organizations here. What clubs and student organizations do you belong to? Have they proven valuable to you?