This question serves a few purposes. It can be a stress test, where they can study your stress responses in real-time. It can also test your emotional intelligence and self-awareness. But the best purpose this question serves is to provide you an opportunity to touch on questions you wish you had answered differently.

When answering this question, never ask the interviewer how they think you are doing. That will undermine your confidence. Instead, inform them of where you feel you could have performed a little better. Revisit any questions you feel you need to and exude confidence and positivity.