<Tr> <Th> 49 </Th> <Td> 13 </Td> <Td> "Great Expectations" </Td> <Td> Michael Grossman </Td> <Td> Eric Buchman </Td> <Td> January 25, 2007 (2007 - 01 - 25) </Td> <Td> 21.50 </Td> </Tr> <Tr> <Td_colspan="7"> After Webber announces his retirement, rumors begin to circulate on his departure and successor . Mark is determined to leave Seattle for good, and irritates Meredith and Alex by making them tend to a patient who will need constant attention but Meredith accidentally gives Mark incentive to stay after letting him know of the open Chief position . Derek is angry at Meredith for causing Mark to remain in Seattle, but soon realizes that she is not the reason he is really angry . The attending physicians at Seattle Grace Hospital fight to get Webber's attention, but he expresses his disappointment in their conduct . He also forces Bailey to get signatures from all the attendings so she can create a free medical clinic, before confessing to her that he thinks she will be Chief one day . Bailey secures the signatures, but has no funding until Izzie offers to spend her entire 8.7 million dollar inheritance on the project . Addison, Izzie, and George treat a patient with a cervical tumor, and Izzie gets worried about George due to his dad having recently died from cancer . Things get more complicated when the patient's Puritan parents arrive . Addison is avoiding Alex following their kiss . Callie and Cristina treat a marathon runner who collapsed after a blackout . George, devastated after his father's death, reunites with Callie and uses sex to overcome his grief, before eventually proposing to her . Cristina and Burke still don't speak to each other, but she eventually breaks, and Burke ends up proposing to her . Webber endeavors to reunite with his wife, Adele, and decides to retire, only to come home and find she's with another man . </Td> </Tr> <Tr> <Th> 50 </Th> <Td> 14 </Td> <Td> "Wishin' and Hopin"' </Td> <Td> Julie Anne Robinson </Td> <Td> Tony Phelan & Joan Rater </Td> <Td> February 1, 2007 (2007 - 02 - 01) </Td> <Td> 24.18 </Td> </Tr> <Tr> <Td_colspan="7"> The race for the Chief's position is on, and the attending physicians, Derek, Burke, Addison, and Mark, compete for Webber's affections by trying to help out everywhere possible . The Denny Duquette Memorial Clinic is open for business, but no one shows up . Izzie is disappointed in what she invested Denny's legacy in, and she and Alex team up to steal patients from the emergency room . Callie and George get back from Las Vegas, announcing their marriage, much to everyone's disbelief . Izzie is not supportive of their marriage and tries to get George to realize the mistake he has made . George and Webber treat a patient with cancer, but her blood has a neurotoxin in it that causes all the staff around her to fall ill . The staff have to operate on her in hazmat suits, and later in small bursts to complete her surgery . Cristina doesn't give Burke an answer to his proposal, but after watching him risk his life during the surgery, she agrees to marry him . Meanwhile, Meredith's Alzheimer's - stricken mother, Ellis Grey, experiences a change in her medical condition by becoming lucid for the day . She is disappointed in the mediocrity her daughter has fallen into and begins to despise Derek, blaming him for what happened to the Meredith that used to be "a force of nature". Ellis has to have heart surgery and, despite her mother's wishes, Meredith schedules the upcoming surgery . Webber talks to Ellis and realizes that she is still in love with him, but she loses her memory after their talk ends, before Meredith has the chance to tell her how she really feels . </Td> </Tr>

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