I feel like they DO hold them...I think I saw ads for something to do with Mac Medicine and something along the lines of MMIs, but I'm uncertain. If you look at the little ad in between the elevators in the Health Sci Building, there's a list of events hosted by the Faculty of Health Sciences/related faculties (I don't know if medicine is its own faculty), and they MIGHT have something along those lines.
If not, I guess the above suggestions sound good too
.
Pre-health clubs --> MMHS? (McMaster Medicine and Health Society) I don't know if they have MMI practices, but you could ask them. Google it and check out their website.