Wexler thinks that because Dr. Seacort has openly stated that he thinks Deep Twelve is damaging the ocean's environment that Dr. Seacort might be trying to sabotage the project. Gaynor is assigned the job of keeping an eye on the doctor. Speed is out exploring in the Mach Five. He discovers a cave that looks like it was bored by machinery. He finds that the cave opens into a big mining operation.
Speed is attacked by the mining machines.
He succeeds in disabling all of them. When he gets out of the Mach Five to examine some of the material that's being mined, one huge mining machine goes after the Mach Five. Speed hops in the car before it gets trashed. He disables the machine and gets away. When Speed gets outside the cave, he sees a submarine which was controlling the mining machines.