Huh?
As Michael recovers in the hatch, he tells everyone that the Others are not that strong. He wants to mount an attack to rescue Walt. Ana Lucia wanted to kill the scheming Henry, but couldn't bring herself to pull the trigger. Michael offers to do it for her. Instead, he shoots and kills Ana Lucia. When Libby startles him, he shoots and kills her, too. He then shoots himself in the arm and sets Henry free. Yes, the word you're looking for right about now is "huh?"