"Don't see why you'd feel bad. The one worried about playin' fair is the one that's gettin' killed first."

Perhaps he worded it a bit bluntly, but the right sentiment is there. Why stress over that kind of thing? As far as he is concerned, anything is fair game once that threshold his crossed. Battle is already dirty enough simply trying to survive. Do whatever it takes to win - that's all that matters.

"It's a part of you, and your enemy's not gonna care when they're dead."