Arnold was the head engineer of InGen. In the past he had worked on projects such as Disney World, and had worked in the Navy. Essentially, at Jurassic Park he had the job of making sure that all the systems in Jurassic Park were running correctly. Along with the rest of the staff, he believed the Park’s safety systems were sound and that failure at Jurassic Park was unlikely, though they had numerous bugs to work on. When Dennis Nedry hacked into the system and shut down the Park, it was Arnold that set to work with fixing the problem. He succeeded for a time, and brought the park back on line. However, he wasn’t aware that the park was running on auxiliary power at that time, resulting in a power failure. Arnold then went to the maintenance shed, hoping to reset the generator and get the Park working again. However, there he was attacked and killed by a Velociraptor.