Jack: "Gentlemen, what do keys do?"
Turkish Pirate: "Keys unlock things?"
Gibbs: "And whatever this key unlocks, inside there's something valuable. So we're setting out to find whatever this key unlocks."
Jack: "No. If we don't have the key, we can't open whatever we don't have that it unlocks. So what purpose would be served in finding whatever need be unlocked, which we don't have, without first having found the key what unlocks it?"
Gibbs: "So we're going after this key."
Jack: "You're not making any sense at all. Any more questions?"