In combat, the rear can quickly become the front lines and when engaged in direct combat, line units cannot come to the support of support elements. If the solider, sailor, airman, or Marine is unable to fight because he is out of shape, he does not need to be a solider, sailor, airman, or Marine.
“soldier” I swear I spelt it that way. I do not know what happened in the post.
Your first assertion is incorrect. Medical personnel can not be required to fight or even be required to pick up a weapon.