If you're a pre-med, quit gunning your first summer a year in advance. Who knows, you might be spending the summer relaxing in a comfortable white vest with tie-around straps trying to get your sanity back. Although, if it's only a 2-week trip, you could apply for positions with the proviso that you need 2 weeks off in June. Miracles can happen when you just tell the straight truth.
Seriously, I wouldn't make MS-I research a huge priority unless you're gunning for Chief Resident at Johns Hopkins. Most of the students I know who did research during MS-I summer were biology majors who couldn't find anything else that paid better. Since I was a non-trad student and my old employer hospital was, God Bless 'Em, kind enough to take me back for the summer at my old rate of pay as a CPA strategic planner - which was 4x or 5x what I could get anywhere else - I was there with bells on for the summer. It's wonderful how much you save on income taxes when you've only worked for three months out of the entire year. Anyway, the extra money helped to pay off my over-budget credit card indiscretions from MS-I year.