In chapter 6, Betty is knocked unconscious when she drives a car through a wall in a parking garage. Despite the fact that no one is driving the car, it makes several sharp 180-degree turns while descending through the garage.
While a prisoner of the Scorpion, Betty manages to grab a gun and fire a shot that creases the villain's hand. Informed of this, Billy manipulates the expedition's members into showing their hands, and only one man's hand shows an injury. However, subsequent events prove he is not the Scorpion. How the real villain had no injury is never hinted at, and there's precious little said about the wound that was found: After Billy escapes a death trap at the latter man's home, the two have a conversation that is joined in progress, with Batson admitting that he could believe the scientist's story (told completely off-screen) about the cause of his injury if he could explain other things that had happened. Perhaps that trap was originally intended to be a chapter-ending cliffhanger and the explanations were lost in re-editing to eliminate a chapter here.