In ‘What Makes Killing Wrong?’ Sinnott-Armstrong and Miller make the bold claim that killing in itself is not wrong, what is wrong is totally-disabling. In ‘After-Birth Abortion: Why Should the Baby Live?’ Giubilini and Minerva argue for allowing infanticide. Both papers challenge the stigma commonly associated with killing, and emphasize that killing is not wrong at some margins of life. In this paper, we first generalize the above claims to the thesis that there is nothing morally wrong with killing per se, so long as it is instant and unannounced. Then, from the perspective of social evolution, we explain why people refrain from killing others, the general guideline being that it is unadvisable to kill someone with whom you associate a Second Person Perspective (SPP). Finally, drawing from a seminal paper of Press and Dyson on the Iterated Prisoner’s Dilemma, we stress that an SPP without an SP (Second Person), or the other way around, can both lead to unwelcome results.