I lay there in the grass, silently stalking my prey - observing his every move. He was a lone guard stationed at a strategic checkpoint. Although he was alone, he was also well armed. If I don't make a clean kill, the sound of combat could give away my presence; or he could easily trigger an alarm calling for reinforcements. The treacherous terrain is easy enough for a lone guard to hold, and virtually impossible to get through if I broadcast my location to a dozen or more armed goons.