Locke hasn't been the same since Ben screwed with his head in the hatch. He kept making remarks about how Jack is the leader and Jack doesn't consult you on stuff and manipulating Locke. Made Locke feel like a picked on cripple again. Brought up those familiar feelings of getting no respect (or love) from his dad, no respect from his boss, used by the undercover cop at the pot plantation... Made our dear Locke snap maybe. Now he is gonna show em who's boss? Maybe?