Alignment Ailment

[Raging Gene Ray]

He explained calmly to the party that if they had just "Killed off all the guards and ran" that no one could possibly know they had even been stopped by them. Like the PC pulled an action that screams EVIL and then hopped behind his CG alignment and claims he is doing the right thing.

Oh...then like I said, tell him that killing people simply for being Lawful is NOT Good. Chaotic, yes. Evil, yes. It's no better than a paladin killing everyone in a Thieves' Guild for simply operating outside the Law. Tell him that if his character doesn't grow and change this sort of attitude, he is going to wind up as Evil. If he has any feats or class features that rely on alignment, strip them until he atones.