Like others, he scoffed at Daniel's theories about the Pyramids not being built by the Fourth dynasty. When Dr. David Jordan began work on the Stewart expedition, he read the carbon dating analysis that indicated they were ten thousand years old, and realized that Daniel was right. Wanting to take credit for himself, he took the Osiris key to the temple it was found in.
Daniel, fearing that he had been taken as a host by Osiris, followed. Upon arriving at the temple, Rayner discovered a Kara kesh and a Goa'uld interactive panel. However, Osiris, having taken Sarah as a host, arrived and seriously injured Rayner. Daniel, Major Samantha Carter, and Dr. Janet Fraiser were able to find and rescue him. Jackson commented that they'd have to come up with a good story to tell him. (SG1: "The Curse")