13 One Shot, One Kill: WHAT DOES GIBBS SAY ABOUT (A SNIPER HAS ALL THE CONTROL AND CAN CHOOSE WHO DIES OR LIVES) PLZ HELP

Not sure if this is the scene you're talking about, it occurs when Gibbs is interrogating Sergeant Barnes. Got it off the episode transcript.

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GIBBS: Maybe you just enjoy being a sniper. You get a thrill out of the fact that your target is totally unaware of your presence. Their lives in your hands. You choosing the exact moment you plan to end it.