His father though straightens him out and shows him that he can help, which garners Don's gratitude — this surprises Alan. In "The Janus List", Don sympathizes with the brilliant cryptographer's desire to feel that his life had meaning, showing another side of him to his father, as he usually would not appreciate any sentiments of a criminal. Though "Number-vision" (as it is called in the special features of the DVDs) usually only appears when Charlie's mind draws mathematical connections, it has been used twice to show Don's mind drawing connections in a similar fashion: 1) During the pilot episode, Don was examining a crime scene relating to the investigation of a serial rapist. While examining the position of cigarette butts on the scene, he suddenly drew several connections and determined the suspect's real motives for breaking his apparent pattern. 2) During "The Janus List" (Season 3 Finale), Don is looking at pictures of the placement of explosive devices on a bridge in the L.A. office with Charlie. Without warning, he sees a pattern in the explosives that translates into a musical scale, much to Charlie's surprise. This pattern, though something he initially shrugged off as a coincidence, turned out to be part of the key to revealing the Janus list and Colby Granger's position as a spy for the Chinese government. When Colby escapes in Trust Metric, Don is conflicted about tracking Colby, and does not know whether to trust him about his status as a triple agent. However, he and his team are hopeful and rescue him anyway. Prior to his escape, Don mulled over Granger's confession for five weeks. In the episode "In Security," Don hides the level of intimacy he had with Leah Wexford and information contained in clearanced FBI files therein concerned, after she is killed. He appears close to her son, comforting him over his loss. Don feels overwhelmingly guilty, and so Charlie performs a Classification And Regression Tree (CART) analysis behind his back. The result shows that he was not responsible for her death, and that his assertions of such lessen Leah's bravery. After protecting Robin Brooks, he has become close to her and they are dating again. In the season finale, he is upset that Charlie cannot help him anymore due to his extreme act of sending his friend's work to a terrorist. He drives off alone to another case. When season