Perhaps you'd like to do a little more reading on the topic first.

The casualty rate was lower in the elite units than in the conscript infantry platoons. Unlike the drafted people, the elite units are entirely of volunteers and well trained prior to deployment. In these units, there were lower incidents of drug use and lax discipline which was a terrible detriment to combat efficiency and safety.

Again, it's safer to be a SEAL or Ranger or Airborne than to be a line-grunt forced to patrol the jungle on foot.