I am confused by your post. Are you looking to apply to “top 10” medical schools? Are you aware that getting into any medical school is a long, competitive process? Many don’t get in at all, and you need to apply wisely.
I would choose what you like, but personally I would choose the research (you will still need to shadow at some point). Would you be shadowing a surgeon for an entire semester? Is there an opportunity to shadow other types of doctors as well- pediatrician, family medicine, etc?