One of the main focuses of the interview is to determine your chances of success in the program. They want to know how well you study, how well you work with others, and how you handle stress. If you have any stories of how you dealt successfully with a difficult situation (ideally academic) that'll help.
They also wanna make sure you're not "crazy". You have to have potential to succeed not only academically, but clinically as well. And by clinically, I not only mean clinical skills and decisions, but what will your chair-side manner be? Can you talk to people without making them feel awkward or uncomfortable?
Convey to them that regardless of whatever hardships may come your way, you will do your best to succeed in the program whether it be putting in extra time, work, etc.
Keep your responses relevant and make sure to showcase your commitment to the program and the profession. You're supposed to be there because you really WANT to be, not because it's convenient or for some other weak reason. Convey all of this and you'll be a pretty decent candidate. Your academics and scores were what got you the interview... be ready to explain any glaring issues in your academic history and turn it into a strength or a lesson learned.