alright, so I don't post usually, but I felt I at least had to put my opinion as far as these international medical missions.
In theory, they sound like a great opportunity and resume builder during the MS1-MS2 summer right?......it is....up to an extent. I personally went to costa rica during my undergrad years hoping to put the medical mission on my resume. It was a 2 week program where I had to pay for my own ticket and all expenses incurred there (although I do have to say it was a legit program, I forgot the organization, sorry).
As far as experience, its almost like....a guided tour showing you the poverty in certain locations. the extent of help you'll be doing will go along the lines of visit and talk to the families, pass out clothes(that you bring to donate of course) and other random tasks. You MIGHT do a brief physical (vitals...weight...) and MIGHT sit in with the doc. essentially don't expect to get ANY medical experience, especially if you're already a med student, you won't learn anything new there (come on...vitals?)
In the end, all you can put on your resume is a 2-4 week trip that cost you in the thousands of dollars. None of the interviewers ever asked me a question about it, it seems like only long term missions are worth anything.
so if you're just looking for traveling with the added bonus of helping people, do it, but don't do it if you're thinking it'll help greatly on your resume. 🙂