Allison Cameron works in the ER. She's much happier there than she was as a member of House's team, though she returns to the latter early in season six.
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Cameron pleads with House not to ask a patient to essentially kill himself in this scene from "Simple Explanation." The main storyline of the hour, however, was Kutner's suicide.
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Here's a shot of Chase and Cameron from season three of House. They haven't exactly received a lot of screen time since then.
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Cameron took over Cuddy's job for the episode titled "Big Baby." This change didn't last long, however.
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On House, Dr. Cameron is often the voice of reason. She's played by actress Jennifer Morrison.
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House Quotes

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House

Masters: Why is your assumption of his guilt more valid than my assumption of his selflessness?
House: Because my assumption is baked up by millions of men, and Taub, who cheated on their wives.