The medic could definately wear a helmet with good visibility, like pilot, or security, and maybe one of the types with the "torch" although im pretty sure its a camera, hence "RS, remote sensor". Although GUNGNIR, CQC, or anything with the headband thing, have a great place to put the little red cross thing. Also on another topic, maybe he could carry those little white medical kits you've seen since halo one, and just throw them to people, becasue most ODST's or marines have some medical training.