If you're doing interviews with multiple schools, you'll inevitably encounter an interviewer who has gone rogue. They might ask something completely bizarre because they're new at this or (and this is rare) in a terrible mood that you must ignore and overcome. Try not to visibly react to either. Instead, try this:
"Can you repeat that?"
If you're unclear on what they are talking about, ask for a repetition. Often, they won't just repeat what they've said but explain it differently, more clearly. If they repeat it verbatim, at least you'll have had 20 seconds to absorb it. If you did understand the question, you can ask for a repeat to give yourself that 20 seconds. Travel back to that childhood spelling bee. Sometimes you asked for the judges to use the word in a sentence because you were looking for contextual clues. Other times, you were buying yourself some think-time. Revisit that strategy.
You could also respond with: “That's an interesting question. I want to think about that for a moment.": Slight flattery, followed by a second to gather yourself. We had a client who was asked what she would do if she did not become a doctor. She took a beat and confidently answered a question she had not seen coming.
Keep Calm and Carry On
Interviewing is a nerve-wracking process. Ninety-nine percent of interviewers will encourage you to relax. They want to know you, not grill you. Then there is that one percent…
An interrogative interviewer might be testing your ability to maintain your composure. Or they might be a jerk who loves being a jerk. It doesn't matter. What matters is your focus on why you'd be an excellent addition to their school and a top-notch physician.
Once, an interviewer interjected as a client shared a college experience to say: "I've never even heard of where you went to college." Without displaying any negative emotion or slamming another school to praise her own, she explained that it was the college that offered her the most academic scholarship money and that she'd had so many hands-on experiences there. She was even credited on a professor's academic paper. Her response was calm and detailed because she'd utilized her brainstorm notes about her formative experiences so often when preparing her application. She nailed it: She was able to naturally remind this guy of her academic scholarship, prove her practicality, and mention a noteworthy accomplishment. Even her interview adversary had nothing negative to say about this response.
Related:
What to Expect in Your Traditional Medical School Interview: Wildcard Questions
The Medical School Interview: Don’t Forget, You’re Interviewing Them Too.