After George talks to Dr. Burke about a biopsy, the camera shows Cristina's procedure on the board and we see the term "salpingo-oopherectomy", which would be spelled "salpingo-oophorectomy" - the surgical removal of a fallopian tube and an ovary.
Dr Bailey is in the operating room holding Cristina's head. She comes to the door to talk to Meredith, and while she is talking, looks back to the operating table where Cristina is lying. Bailey's hands are visible in the close-up of Cristina's face even though Bailey is now standing at the door.
When Addison and Derek are in the room with the premature baby addicted to narcotics, Addison is listing options for her and Derek's relationship. The chair that Derek is sitting on has a blanket draped over it and it changes position throughout the scene many times.
At the beginning of the episode Dr Webber is speaking to Dr Shepherd in the lift. The bandages from his surgery are clearly visible under his hat. However when he is speaking to Dr Shepherd from outside the lift without his hat on, the bandages have disappeared.