Complex sentence: Five hundred of the 600 volunteers that Darby brought with him to Achnacarry survived the Commando training, many could not endure the exercises, one Ranger was killed, while several others were wounded in training so realistic, it was actually executed under live fire.
Split into simpler sentences: Five hundred of the 600 volunteers that Darby brought with him to Achnacarry survived the commando training. Many could not endure the exercises; one Ranger was killed, while several others were wounded in training so realistic, it was actually executed under live fire.