Odd scene

Near end of movie the troops are holed up in a cave and a ricocheting bullet kills off the sarge. Then, suddenly, we see them leave the cave, carefree as hell. Are we to believe a wild bullet shot into the cave's entrance can knock off the sergeant, yet they casually leave the cave like no enemy troops are waiting to mow them down? All in all, a darn good movie, and didn't Basehart look sooooooo young?
Mountain Man