It's no myth, it's the reality: when you go into a combat zone, injuries happen. The most dangerous are those which result in immediate death. Next in order are the aptly named Fatal Wounds. A wounded soldier loses as many HP's per turn as Fatal Wounds she has, until patched up or dead. Loss of health reduces all Combat Skills, reduces Energy Recovery and inflicts constant Stun damage. Fatal Wounds to arms and head drastically reduce Accuracy until healed, same with torso wounds reducing Energy Recovery and leg wounds - TUs.
We'd like to experiment some more, Cap'n, but the hands are reluctant to participate, would you help us catch some volunteers?