build a life and not a resume. Don't approach everything with the mindset of "will this look good or bad on my medical school CV" because you lose a lot of valuable life experience by just doing. The important thing to keep in mind is how you tell the story. If someone asks you what you did those 3 weeks and all you can say is nonsense then it's not worthwhile to put it on your CV but if you can intelligently discuss what you did than that's fine. A lot of premed approach med school application like a to do list. Quantity with little depth once you probe deeper than the surface. It's pretty obvious on the interview portion. The ones that do well are the ones that are more than their CV and scores.