Jonah was the personality stamped onto Col. Jack O'Neill on the planet P3R-118. (4.10 "Beneath the Surface")
Jonah seemed satisfied in his life as an underground power plant worker on the planet P3R-118. His personality stamp gave him memories of working in the mines and being a foreman there before being transferred to the power plant. He usually kept to himself, but started to show special attention to Thera, the personality with which Maj. Samantha Carter had been stamped. They started to talk to each other and Jonah kept his eye on her and encouraged her to approach their supervisor, Brenna, with her ideas on how to improve the operations of the plant. They slept in the same bunk room, but were a few bunks apart.
Jonah didn't like Kegan, the woman who served his section their meals. Kegan consistently showed her dislike for Thera, constantly denying to serve Thera bread. Jonah had had enough of this ill-treatment and grabbed Kegan's arm and demanded that she give Thera her bread. Carlin (Daniel Jackson) tried to push Jonah away and the two men got into a fight. It was at this point that Teal'c's stamp failed and he remembered that Jack and Daniel were friends and belonged on SG-1. He urged them that they must escape, but he was taken quickly away and everyone was told that he was night-sick. What Teal'c said did not mean anything to Jonah, but he cowered when he saw Teal'c back as a worker in the plant a week later.
Carlin couldn't let what Teal'c had said go, however. He pushed Jonah and Thera to remember everything about themselves, something he found he had a problem doing. Why would Tor (Teal'c) say that they were friends and he couldn't remember? Jonah didn't want to remember. He seemed content to do his duty and spend as much time as he could with Thera. When the three of them started to meet in secret, something which was not supposed to be done, Jonah would meet with Thera alone so that they could cuddle. He never seemed to have had the idea to meet with Thera alone before Carlin began pushing them to break the rules, something which Jonah felt a great deal of duty to uphold. He also feared getting rations taken away from him as punishment.
After Brenna revealed their identities to them, SG-1 quickly began to remember who they were. Jack's memories came back to him quicker, perhaps due to his special ops training. He resumed his role as leader of SG-1 and revealed to the workers that they had been lied to about the city above them. When he and Carter were alone together, they realized that their attraction toward each other might have been due to the personality stamps, but they also recognized that it could have come from something deeper. They remembered that they were officers in the USAF and that he was her commanding officer. Any genuine romantic feelings he had for her and vice versa were quickly swept aside as they resumed their roles as teammates. (4.10 "Beneath the Surface")
--DeeKayP 10:19, 13 Jun 2005 (PDT)