<P> Early in Season Three, Susan Lewis leaves for Phoenix to live with her sister and niece . Before she leaves, Greene realizes his feelings for her and races against time to declare them . He makes it to Union Station just as she is boarding the train . He stops her and declares his love, begging her to stay . Susan leaves anyway, but not before kissing Mark and declaring, as the train pulls out of the station, that she loves him too . In the aftermath of her departure, Mark falls into depression, develops a meaner attitude, and starts sleeping with County General nurse Chuny Marquez, although they soon break up . Towards the end of the season, he is attacked in the ER bathroom, and the thug is never caught . Although some suspicions arise over former patients and families, his beating was no more than a random act of violence . He becomes increasingly paranoid about his personal safety and distances himself from friends and family . </P> <P> Meanwhile, Doug and Carol draw closer, culminating in a kiss at the end of the season . Doug is said to be attending therapy throughout the season, although this is never shown on - screen . This is possibly due to one of his one night stands dying in the hospital just after they were together, and Doug questioning his actions . Carol considers going to medical school, but eventually decides that she loves her work as a nurse too much to change . </P> <P> Carter, now an intern, continues to lock horns with Benton, especially over Benton's treatment of surgical intern Dennis Gant . This eventually results in Gant dying by suicide by throwing himself in front of a train and despite the ER staff's best efforts, Gant eventually dies from his injuries, devastating Carter who begins blaming himself and Benton for not doing more to prevent Gant's suicide . </P> <P> Benton also starts dating Carla Reece, who becomes pregnant and gives premature birth to his son at the end of the season . Weaver supports Jeanie, who is forced to reveal her HIV - status early in the season, when Mark gains unauthorized access to her medical records . While Jeanie struggles with her condition, she becomes involved with a doctor from the Infectious Diseases department, before reuniting with her ex-husband, Al . </P>

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