Betterment of men or betterment of me?

Extract

[...] More commonly known as the golden rule, this statement explores the idea of utopia via individual actions. If everyone treats everyone nicely, everyone will have a happy life. However, for one person to dislike anything the whole structure falls apart and the utopia dissolves into a dystopia. It seems easy enough to never do wrong, but what if wrong is being done to you? Can you protect yourself without doing wrong unto another? Yes, preventing harm to yourself is good. [...]

[...] Well, as McMahan points out, “killing a rational, self-conscious being is wrong because it involves a failure of respect for that individual as a rational being.” (McMahan, Ethics of Killing) So, man and animal are in essence the same, but because man possesses the ability to think and argue rationally, as opposed to a cow, killing a human is evil. In order for a killing to be considered immoral and evil, the organism has to be aware that it is being killed and rationally consider the full implications of this act. [...]

[...] Betterment of men or betterment of me? To regard one person's life as more important than another's can present a morally disturbing argument. If the death of one individual can prevent the deaths of twenty, do you sacrifice that one person? What if, to save those same twenty, two must be killed? How about five? Can one rationalize the killing of some to save others? This is the view of the utilitarian perspective which posits that whatever can be done for the greater good, must be done, no matter what needs to occur. [...]