Others have have already answered this somewhat, however I think they may be incorrect about extra spots for MMTPs. But that doesn't mean that your concept of how it works would then be correct.
DND has subsidized additional medical school positions above the provincially funded quotas in recent years (
and not so recent - but I'm an old fart so even 'not so recent' is since I retired from the CAF). But that still isn't a guarantee that a MMTP applicant would get a spot or that it would even be filled in a particular year.
Let's take Alberta as an example:
www.ualberta.ca
I don't know what province/school you would be applying to, but you'll probably find a similar policy everywhere. If you're not competitive for med school when you're a civilian, it's unlikely that you would be competitive as military. Or at least not as you suggest, doing the bare minimum service to become eligible. I'm not a doctor, but over the course of my military career I've known and worked with several, served under a few and count as friends a couple of individuals who became military physicians through MMTP, including at least three who went on to become Surgeon General.
While there isn't a cookie cutter profile of their pre-med school service, they are/were generally highly motivated, intelligent individuals. A lot of them started by going to mil col then spending several years as pilots (jet and helicopter), infantry officers, engineers (construction, electrical, mechanical, computer) or naval officers before applying to med school. At least one I knew started in the ranks, became a pharmacist through UTPM and then a doctor through MMTP. There were others who came through the route of either ROTP (civvy u) or DEO before MMTP but they did the same as all the others, spending years in another military occupation where they were always top performers and if they hadn't gone to med school would have been promoted into senior officer ranks (actually, there were a couple who had been promoted but gave up the extra half stripe to do medicine).