If you are serious about pursuing the MD/PhD application, you should check out the physician scientist forum - the people there may be able to give you more insight.
Just a couple of things to consider though,
1) A 30 is low for MD/PhD admissions. I had a 32 when I applied and I got REAMED by most of the schools I applied to. Everyone drilled me about it, and many people told me I wouldn't get in because of it. Just a warning.
2) Two summers of research experience is very low for MD/PhD admissions. Most applicants will have two full years or more of experience - including independent handling of projects, a strong role in designing projects and seeing them through to the end, and presentations/posters/publications. In MD/PhD world, it's the depth of your experience that matters, and you may have trouble convincing schools that you have gained that kind of experience in just a few short months.
Anyway, take a look at the forum. It may help.