first of all, i don't give a damn about our judicial system. i answer to my own set of ethics. so the fact that it was "murder", and i'm not at all sure that the example you cited would be, would have no impact whatsoever on my choice. if the decision was mine to make, i would like to think that i would not kill an animal to save a human life, even my own. having never been in that position, i can't say for sure. i could end up being "only human", and give in to my selfishness. i am after all, as imperfect as the next flawed human being.
i don't think i advocated Darwinian theory for humans and not animals. i believe we have the right to eat animals, as all carnivorous animals do. i just don't think we have the right to abuse or torture them in the process. additionally, as the "intelligent" species on the planet (another day, another debate), i believe we have the responsibility to find merciful ways to do so.
in general, all species have the right to survive, it's just drawing where that line begins and ends that is the issue with me. do we have the right to maintain animals in unnatural and often physically restrictive environments so that we can eat them when we feel like it ? do we have the right to mistreat them in the process of raising them, to give them no respect or dignity, or to kill them inhumanely (there's that ridiculous word again) ? do we have the right to experiment on them to unnaturally lengthen our lives ? do we have the right to torture them to prove that our shampoo is safe ? arguments could be made for all of these things being within the category of "survival", but i think that would be stretching the point beyond reason.
Non-violence leads to the highest ethics, which is the goal of all evolution. Until we have not stopped to include violence as an option in our conflict management, we are still savages.
--Thomas A. Edison