Caboose was an AI agent, and he sided with Tex when she tried to find the Alpha. While Tex was searching for Alpha, Caboose was caught. Caboose had his memory wiped, which damaged his intellectual capacity. Note that in his early appearances, Caboose did not have his trademark voice impediment. It was only when Omega possessed him that he degenerated into an idiot. However, no other Omega possessee suffered an intelligence decrease. (ex. Doc) However, Agent Carolina went insane after getting two AI's. Since Caboose only would have had the memory of an AI, he would have only been damaged slightly. Caboose being a Freelancer would explain lots of things about BGC, such as why Caboose arrived in the gulch with a F.I.L.S.S. operated tank, why the Director would let Tex visit the gulch after Si