Every unit I've seen seems to have their cohort of a couple HMs, who usually hang out TAD at whatever base or ship medical facility the unit is attached to and help the docs take care of people from their unit.
So our squadron HMs would usually be found bouncing back and forth at homefield between squadron spaces and the clinic, do the same at Fallon, and then be hanging out in medical when we went underway. I would bet something similar for a NIOC, if more tied to whatever the base clinic is.
Not a doc myself, just what I've seen in my career.