Healer can generate the second highest enmity if the DPS stacked to him, he could still heal himself and hold the mobs.
I can't see a nurse taking scalpel from surgeon to do the surgery. Plus even if it would be difficult, surgeon should still be able to finish the surgery without the nurse.
EDIT: To me you are still just trying to prove your entitlement in "stop being entitled" thread. Which is the problem that most people who disagreed with you had.