I agree, but I don't know what those activities could be.
Well, from my experiences during second look and from analyzing the results of my friends, I would say there isn't a formula for getting into schools like Harvard, Columbia, ect. But a lot of the people I met fell into 1 of 3 groups.
1- people with average stats for top schools (3.8/36) and a unique factor-Rhode Scholar, Concert Pianist, Professional Chinese ballet dancer, Former Lawyer/top Law schools grad, ect (no joke I met all of these people during second look).
2- people with above average stats for top schools- 4.0/40+ MCAT/ lots of research/Multiple publications (the kdizzle and wangers of the world)
3- people with average stats for top schools (3.8/36) with something that stands out. The majority of people I met fell into this group. They had a cool personal narrative or a unique interest or something that made them slightly different. For example: (again ppl I met)
White girl with average stats from an upper middle class background, but became passionate about healthcare issue in Kenya. Ended up majoring in African studies, learning said language, doing her research on healthcare issues in Kenya, took a year off to work in Kenya with red cross.
Black guy from disadvantaged background. First in his family to go to college. Has average stats for top school.
White guy from disadvantaged/rural background. Wants to go into primary care/rural medicine. Has tons of EC devoted to this future dream.
URM with average stats for top schools + went to Yale for UG + good but typical EC
Non-URM with average stats for top schools + tons of research + 2-3 publications
I think a part of it is getting involved in things you are passionate in and whatever drives you to become a doctor. The other part is making this narrative clear in your application and marketing yourself well.