Her words were enough to make any Grey's fan burst into tears, and the letter may have also helped Meredith keep her license after all. The letter also showed a rare side of the Cristina. She was never one to get mushy or overly emotional, but she had her moments — especially with Meredith. One of the best Meredith and Cristina scenes came during Sandra Oh's exit from the show . Before leaving, Cristina told Mer not to let Derek Shepherd (Patrick Dempsey) overshadow Meredith's own needs in her career. "You are a gifted surgeon with an extraordinary mind," Cristina said, "Don't let what he wants eclipse what you need. He's very dreamy, but he is not the sun. You are."