Sorry this happened to you. Sounds like the armpit of the world down there. I guess that you could encounter a mentally ill street urchin anywhere though.
I think although it's a tough decision to use deadly force and Rich Stern spelled it out pretty well as far as the system grabbing you up and politics and luck having a lot to do with your future, you have to also consider that one punch could render you unconscious before hitting the ground which then could cause a fatal head injury or broken neck.