I spent all of undergrad living in the dorms, and I liked living in the dorms at the time--meeting people, meal plans, etc.
HOWEVER, realistically thinking, living in the dorms while in med school could be very bad. If you're in some type of graduate student housing, it'd probably be fine and great for your situation. If it had been a feasible option for me, I'd probably have done it. But if you will be living in the dorms with all the 18 yr old freshmen who are enjoying the freedom from mom and dad for the first time in their lives, you will have to put up with all of the obnoxiousness that goes along with that. My house for first-year was next to keg party central and it drove us CRAZY, especially around exam times--and in the dorms it would be far more annoying and loud to put up with that. Med school exams cover far more material and memorization than undergrad---you'll have to spend more time studying....and you'll likely have less patience in dealing with dorm-dwellers, noise, etc.
What about a roommate? Would you get your own room or would you be randomly assigned with someone? That also could be problematic depending on what type of person your roomie is and how respectful they are of your situation and being a med student. Med school is stressful enough on it's own---try to find the best living situation you can, be that in the dorms or otherwise.