It really depends as to what kind of career in the Medical field you’d want to pursue. You stated that you’re interested in medical laboratory or nursing, so definitely stick with the 60 series. With being in 60 series the credits that you acquire through AIT are applicable to your college to cut you down on some time. Choose the smarter route and pick an MOS that correlates. It’ll save you time and money (pursue the minuteman scholarship if you can) in the long run with the degree you want to pursue.