The only circumstances where I could possibly consider this would be that the victim in question was already dying of an incurable illness. Also this person would not have children or relatives who would suffer because of their death. I do not believe in the sanctity of human life. I do however believe in the balance of suffering and well-being as a measure of morality. Allowing a person who would suffer in agony to slip away peacfully could in the right circumstances be a moral act.
Let me be clear though. I would not and could not do this simply for a payoff. It's unthinkable and detestable to rob someone of their life and inflict enormous suffering for personal gain. That job is reserved for politicians and televangelists.
I'd like to hear more of your philosophy. Why do you not think human life is sacred?
The word sacred is typically used in a sense implying a soul, or at the very least some special quality unique to humans. I believe in no such uniqueness, and I certainly don't accept the proposition of a soul. The universe sheds no more tears over dead people than it does over dead bacteria. I'm not in any hurry to see anyone die, as I hope you gathered from my previous post. I want people to thrive and be happy. I think it's always best to diminish suffering whenever possible. I just don't see any reason to think that people have some special status that makes them objectively more valuable than other life. Definitely they are more subjectively important to us though.
2. Ultimate importance and inviolability.