My suggestion is to have a 'revenge' button on the bottom of an attack report for when you get killed. So for example if a hitman killed me I could press the 'revenge' button for say 10 credits and it would send a virtual hitman after who ever killed me and would kill them. I'm guessing this resulting in any stat change would throw out the balance of the game so it would purely be there for the satisfaction of causing whoever killed you to be mildly inconvenienced by being sent to hospital.