#1441: Turnabout explain

[A guy and Cueball are engaged in a fight with laser pistols. The guy is standing behind a small box, firing his gun at Cueball.]

[Cueball is kneeling behind a larger box, returning fire.]

[The guy leaps on top of the larger box, knocking Cueball backwards and off balance. Cueball fires wildly into the air.]

[Now the guy is standing on the box. Cueball is sprawled on the ground, laser pistol out of reach, at gunpoint.]

Guy: Any last words?

Cueball: “Apollo retroreflectors.”

Guy: What?

[The guy gets shot in the back by the returning beam of Cueball’s wild shot.]