Getting accepted into a BS MD program is incredibly competitive. If you have filled out the application and made it to the interview round, congratulations! The interview is the next step in the process and how you perform is critical to your admittance.
The interview process varies from program to program. Sometimes, you will interview at the undergraduate institution. Other times it will be at the medical school. You might even meet at the teaching hospital associated with the program. Many times they will do an initial phone or Skype interview, especially if you are located across the country.
The BS/MD or direct medical program interview helps to bring you alive outside of your application. The interview serves to give the school a better insight into you as a person, beyond just your test scores and transcript. You won’t be quizzed on your current medical knowledge; instead, they want to learn about your opinions. Since you have impressed them with your application, the interview is the time to show them that you are who you say you are.