By PAULINE JELINEK and CALVIN WOODWARD Ordered to shoot to kill, snipers on the heaving stern of the destroyer had one improbable chance to get it right.Anything less than direct hits killing three pirates with three bullets would have placed the American hostage, merchant Capt. Richard Phillips, in mortal danger, if not sealed his fate.The scene was set as darkness fell Sunday evening off the African coast: The last three pirates, holding Phillips in an enclosed powerless lifeboat, appeared to be running out of patience with their predicament.Bobbing for days after their brazen attempt to seize Phillips' ship failed, their mood was "going up and down" like the ocean swells, according to U.S.