3x6 - Grey's Anatomy

Cristina gets to scrub in on a rare surgery which incites envy. Alex questions his future in plastics. George and Addison work together with Noelle. Noelle is pregnant with twins but one of them is growing slower than the other. Her fiancé has problems of his own. Derek's sister visits. A patient's wife makes things hard on the staff since she has made her husband's health her job. A woman's sexual exploits are questioned.