The ethical basis of suicide prevention is illustrated by contrasting helpline emergency rescue policies of the Samaritans and the AAS and the U.S. National Suicide Prevention Lifeline network. We contrast moralist, relativist, and libertarian ethical premises and question whether suicide can be rational. Samaritans respect a caller's right to decide to die by suicide; U.S. helplines oblige emergency intervention during an attempt even against the caller's will. We analyze the effect of emergency rescue when there is high suicide risk but an attempt has not been initiated. We examine links between values and actions, needs for empirical evidence to guide practice, and propose vigorous dialogue about values in the gray zone of moral practice.