I was in the afternoon session, so arrived at 11:45 for a noon start. There were 6 of us in the group, as well as 6 tour guides. You sit there chatting for a while and they take everyone upstairs for an information session. Then, they had the order of interviews (this is total conjecture, but they might make the order based on order you show up. It could be coincidence, but the guy who interviewed first arrived last, and I was second to last to arrive and interviewed 2nd). Interviewees 3-6 went on a tour while we hung out (great opportunity to talk to tour guides because at that point, the first interviewee was in his interview and it was me with three tour guides). Then I went in for my interview, which lasted about 25-30 minutes. Then you come out, eat complementary food in the cafe area, and interviewee 1 and I went on our tour while the rest of the group came back to interview. We got to see 2nd years in lecture and 1st years in OMM lab, which I really enjoyed-helped me envision what being a student there would look like.
Everyone kept saying how the interview was more of a conversation, but personally, I wouldn't really agree with that. Perhaps it was because it was my first interview, but it was more of a direct ask and answer type deal. I was also worried that my interview was short, but I ended up getting in, so I'm not going to dwell on that now. I hope this helps, and best of luck!