Sometimes people who have been through a traumatic experience repeatedly replay that experience (either in their mind or in life) in order to try to gain some mastery over their feelings of helplessness and pain. I may be reaching since I don’t have a lot of information, but it seems possible that the suicide of a friend was traumatizing for you. Why wouldn’t it be? Now you are separated from feelings of love, compassion, and connection and are replaying death scenes over and over. You’re stuck in this go-around until you find a way out. You seem to think that killing someone will do it. It won’t. It will only reinforce the problem. What will help is reconnecting with the good person you’ve always been.
What makes this lack of feeling even more dangerous is that you are a military man. You probably have access to guns and you’ve probably had training in how to kill.
Please — prevent yourself from doing something that will destroy someone else’s life as well as your own. Get help! Now! You’re not “too far gone.” Writing to us here is a statement that you haven’t given up on yourself. A place for you to start is the huge VA hospital near you. Military psychologists are particularly well versed in the various ways that people do and don’t manage traumatic experience.
I wish you well.