Psychological egoists argue that everything we do is self-serving even if we might think it is not. Self-sacrificial behaviors, such as using oneself as a human shield to protect others in a mass shooting, cannot disprove psychological egoism because people who sacrifice themselves are not motivated by altruistic concern. Rather, they do what they most want to do. Sacrificing one's life happens to be what one most wanted to do in those circumstances. Given that doing what one most wants to do is in one's self-interest, one's "self-sacrificing" behavior is again egoistic. 

Do you agree or disagree with the above ? Explain with proper reasoning.