3x09 - FROM A WHISPER TO A SCREAM

Derek: No, no that is not how this works. How could you know what you know, or suspect it and not even tell me? Meredith: You cleared him for surgery Derek. How did you not know? You can't be angry with me. She's my best friend, and right or wrong she... Derek: What? Meredith: She was there when you weren't.