When Clark/Kelly kills Rick before he kidnaps Billy, he stabs Rick in the chest and almost cuts his heart out. Clancy says that Clark "felt the heart trying to beat, but destroying itself on the double-edged knife." Kelly earlier referred to the knife specifically as a Ka-Bar.

Later, a policeman looks at an imprint made Kelly wiping the blood off the knife and clearly identifies it as a Ka-Bar, saying that "the Marines must have enough, now the Boy Scouts can buy them for $4.95."

There's only one slight problem. Unless Clancy refers to the unsharpened false edge as a second edge, Ka-Bar has never made a double-edge knife. Even calling the false edge a second edge is a fallacy because the false edge only extends 2" of the knife's 7" blade.

For dramatic reasons, this works well, but in the real world this would never happen.