The villian's last words were a callback to his earlier dialog.

Howard Payne: Pop quiz, hotshot. There's a bomb on a bus. Once the bus goes 50 miles an hour, the bomb is armed. If it drops below 50, it blows up. What do you do? What do you do?

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The writer also uses this dialog piece "pop quiz" with another character.
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Harry Temple: All right, pop quiz. Airport, gunman with one hostage. He's using her for cover; he's almost to a plane. You're a hundred feet away... Jack?

Jack: Shoot the hostage.

Love the replies Jack has for this question and the last words.

"Yeah? But I'm taller!"