As a pre-med student who's done a LOT of hours in hospital settings... I just can't find them sexy. We once had a patient try and pull out his catheter. YEEEOWTCH!
A also personally am not into the whole teacher/student role. It must be something about the age difference and such (though I don't have anything against couples with large age gaps) that just sort of turns me off.
But to each their own! If these roleplays are what get you off and let you have a safe outlet for your desires go for it.