Ahriman's whole Hoist by His Own Petard moment. He took on a patient solely because he thought her obsession rare and interesting—she's the rich wife of a would-be politician who is fixated on Keanu Reeves. After turning her obsession into a phobia, he dismisses her as a ditz, and tries to put her off temporarily by telling her the The Matrix is real, and she needs to lie low for a while. It works, but she decides he's an Agent and shoots him dead in his own office. Then hires his secretary.
The bit where Ahriman realizes his hold on Martie and Dusty has failed, and winds up in total disbelief that "a video-game designer and a housepainter" could possibly outdo him. It's the beginning of his long, very satisfying downward spiral.