Suppose I murder someone, am tried, go to jail for 20 years. I am released. According to what you say, it's irrelevant whether I kill someone else now, since I'm already "evil." The number of additional people I kill is meaningless. I would argue that we classify "evil" based on the grief that it would cause. In the scenario I present, there would be an entirely new group of people (friends and family of the victim) grieving. The amount of harm I've caused to society is now double what it originally was.

With this in mind, what's the difference between committing two murders, separated by 20 years, versus killing two people simultaneously? The grief caused in both cases is equivalent, just one is disjoint time-wise from the other. In that respect, I'd say it is most definitely worse killing two people than one.

Note that I'm not referring in any way to killing one person in order to save two. I agree with you that doing so is unjustified (by the way, this is what Rand does, and you are defending him). However, you seem to think that the term "evil" is an all-or-nothing label, and once you are evil, the amount of damage you do to society is irrelevant. Wiping out a city or killing a single person--both evil!