2x10 Much Too Much
Meredith tries to dismiss a one-night-stand from her house much like she did Derek many months earlier -- and like Derek, she's surprised to find the guy at the hospital later that day. Unlike Derek, he's not a doctor but a patient. He has an erection that won't quit, and actual requires medical attention from Meredith, Cristina, and Bailey. For all intents and purposes, it looks to them like Meredith broke the man's penis. And when the cause of the "priaprism" cannot be diagnosed, they have no choice but to call in for a neurological consult -- from Derek himself. Cristina wakes up to find that Burke has "keyed" her. He not only wants her to have a key to his apartment, he actually would like for her to move in with him. Cristina has issues with this, and she takes Burke to her apartment to show him just how bad of an idea that really is -- Cristina is the single messiest person in the world.