Overview: A devastated Cristina presses Owen to confess the intimate details of his affair; Mark takes his new authority very seriously when he steps in as chief for the day and butts heads with Richard over a patient's liver transplant; and Callie deems Meredith ready for the boards, while the rest of the residents continue to stress about the exam. Meanwhile, Callie, Arizona and Bailey plan a much needed ladies night for Teddy.