Emanuel said the Hippocratic Oath and the codes of modern medical societies require doctors to maintain client patient confidentiality, refrain from lying to a patient, keep patients informed and obtain their consent, in order to protect the patient from manipulation and discrimination. Emanuel said that a doctor’s oath would never allow him to administer a lethal injection for capital punishment as a doctor, although the issue would be different if he were asked to serve on a firing squad not as a doctor but rather as a citizen. He said that in the case of mercy killing there are rare cases where the medical obligation to relieve suffering would be in tension with the obligation to save a life, and that a different argument (an argument that intentional killing "should not be used to achieve the legitimate ends of medicine") would be required instead.