unless you do electives, most people won't get much exposure to the surgical sub-specialties (ortho, ENT, uro, plastics, neurosurg). I'm not going to have any exposure to interventional radiology, rad onc, PM&R, rheum, ID, neph, heme/onc, or a number of other specialties. I've did an elective in EM as an M3, and I'll do one in cards, path and radiology as an M4, and I've worked with pulm/GI/cards on my medicine/peds patients. I had an M3 anesthesia rotation, but the rest of my M3 courses were the usual.