Just for general info, most services require newly minted O-1's to serve at least one tour, sometimes two before sending them to grad school whether it be Law School, Med School, or Advanced Engineering School. And if you get selected, I believe it is two for one additional commitment IF you are selected. So if you went to Medical School for three years and a residency, you would owe service eight additional years. Most of the military uniformed docs are Direct Commission, meaning they attended grad school on a scholarship or their own dime then committed via the Direct Commission Program for whatever Branch they desire. This is true for most of the docs, dentists, and lawyers. Very few get sent after graduation or even after becoming eligible, it is just more cost effective for the military to Direct Commission already qualified grad students, especially for JAG and Medical Corps. As
@conrack related, VMI, the Citadel, or other ROTC Programs Commission far more Doctors, Dentists, and attorneys than the academies.