Have you ever felt an inherent rage for a villain to the extent that you actually felt bloodlust? 
> 
Yes, but not a villain from a movie or other fictional work.-> What I mean by this, is that the images evoked within you were so powerful that the urge to destroy brokered no feeling of remorse whatsoever?
> 
Yes, and that is one of the primary functions of anger. -> 
> In modern society, one thing that most of us never get to experience is the direct threat of loss of life for ourselves or our loved ones by another being. 
> 
> What role can rationality play when faced with an extreme such as this? When does Utilitarian Ethics win?-You come to the realization that there is a distinct and vital separation between anger, hatred, and the act of destruction. When anger reaches a certain point, at least for me, it becomes calm, cold dispassion which allows me to do whatever is necessary without being emotionally involved. -While serving in Iraq, many of us that were there at some point got to this stage. It is the point where you can destroy simply because something needs to be destroyed, and the anger itself acts as a protective insulation for your sanity. Ironically, the only other emotion that can provide that same level of insular protection is love. (i.e. When you a person or creature so much that you would rather end their life than see them suffer another moment of pain.) I do make a distinction between the love that will protect you when faced with a choice such as this, and sympathy which will almost always leave you with doubts and regrets that claw at your sanity.