William was a serial killer on death row who got shanked. Seeing as he'd killed five women and seemed to have no remorse (and was headed for a lethal injection), Derek wasn't exactly psyched about treating the patient. Upon hearing that Dunn was a perfect match for a young patient in need of a transplant, even Bailey considered leaving him for dead on the operating table in order to harvest his organs. Dunn even tried to brutally kill himself in the hospital -- by bashing his own brains in -- so that the young boy could benefit from his death. No dice, though... Dunn was killed via lethal injection. Meredith attended his execution. His viable organs were wasted.