Obviously can't share details, but I had so much fun in their MMI. I find MMIs really stressful generally, but theirs I legitimately was able to relax and enjoy. Try not to stress about it too much. They really try to put you at ease. Also remember you're not competing against anyone else for a spot. If you make it to interview, they are just trying to decide if you and UMich are mutual fits for each other. They have a very high post-II rate, so it's not like other schools where only 1 out of 5 interviewees get in. If you do well and so do the people you're in the MMI with, you can all get it. Just get through it together and have fun. If you want to prepare, their website has lots of useful information that will give you a sense about what the school cares about. Good luck!