Every time they operate, surgeons are betting their skills are better than the brain tumor, the faulty heart valve, the fractured femur. Sometimes, they're wrong. At Chelsea General, surgeons answer for bad outcomes each Monday at the Morbidity and Mortality conference, known as M & M. An extraordinary peek behind the most secretive curtain in medicine, following the lives of five fictional surgeons. From the practicing neurosurgeon who is CNN's chief medical correspondent.