Gina Roberts is a hostage negotiator for Homeland Security.
She was called into Stargate Command during an attack on the Stargate. She was supposed to talk down Chief Master Sergeant Walter Harriman, whom she believed had Sergeant Sylvester Siler hostage and thought he had made a deal with the Lucian Alliance. This assumption was due to Harriman being close friends with another SGC personnel who had turned and had used one of his shifts to dial the gate, unbeknownst to Walter.
After the situation was resolved, she and Walter made up and had dinner together. (SG1: "Lines of Communication")