Grant suggests that, despite the precautions that have been taken, the dinosaurs may be able to breed because Dr. Wu has substituted frog DNA in order to fill gaps in the dinosaur DNA they retrieved from amber. Hungry for dinner, Tim, Lex, and Regis get in one car, while Malcolm and Grant get in the other. Sattler stays with Dr. Harding to tend to the sick stegosaur, and Gennaro joins them so that he can flirt with Sattler. Malcolm is worried because chaos theory predicts that a sudden drastic change will take place on the island soon.
Playing around with some binoculars, Lex spots several small velociraptors on the supply ship that has just left the island. Meanwhile, Nedry jams the computer system and phone lines so that he can sneak into the fertilization room and steal the embryos without setting off the security system. Nedry then takes Muldoon's jeep to drive to the dock. Arnold realizes that Nedry has turned off the security systems, and realizes that the electric fences keeping the animals confined are therefore no longer functioning. Furthermore, Nedry's power cut has disabled the tour cars, leaving the tour group stuck in the now-motionless cars. Muldoon leaves to go get the tour group, but suddenly realizes his jeep is gone.
In this section, Crichton increasingly incorporates elements of science into the book. Graphs, charts, DNA readouts, and lots of scientific background information are included to help explain how dinosaurs could be cloned and what sort of high-tech measures might be employed on an island that tried to contain them. Malcolm's discussions of chaos theory becomes more frequent and detailed, foreshadowing something uncertain and ominous. Although chaos theory implies that the activity of a complex system such as Jurassic Park cannot be predicted, Malcolm says that this very unpredictability implies that something unpredicted will happen.
As the plot gains momentum, the chapter titles begin to alternate in a regular manner. Every other chapter has a descriptive title, such as "The Tour" or "Big Rex," interspersed with several chapters that are titled "Control." In one sense, this name is appropriate because the narrative perspective is switching back and forth between the control room and other areas of the park. The word "control" is also a scientific term, however, referring to a convention of scientific experimentation. If a scientist is studying the effects that a chemical has on wood, for example, he or she will ready two samples of wood and add the chemical to only one of the samples. The untreated sample becomes the control group, and the scientist determines the effects of the chemical by comparing the piece of wood that has been treated to the one that has not. In other words, the control group should remain the same throughout the duration of an experiment.
This idea of the control group can be applied to this section of the novel. The control room of Jurassic Park is supposed to be able to keep the entire island stable and in check. Throughout this section, the narrator's perspective shifts from one part of the park to another. Each time this happens, the reader gains new and unsettling clues: The baby raptor that jumps into Tim's arms looks and behaves just like the animal that attacked Tina, leading us to wonder whether raptors have reached the mainland. Even Dr. Wu becomes nervous about the animals he is creating, as more and more evidence appears indicating that the dinosaurs are breeding. Throughout these revelations the perspective repeatedly returns to the control room, but the control room appears less and less stable each time we return to it. We get glimpses of Muldoon's and Arnold's nervousness that reveal obvious flaws in Hammond's organization of the park. Finally, when Malcolm exposes defects in the park's computer system, the dependability of the entire control room is suddenly called into question. If we consider Jurassic Park one big experiment and the control room representing a supposed force of constancy, just like a scientific control group, by the end of this section we get the sense that the experiment has gone seriously awry.