I think if most of you killed someone you'd be haunted by the memory for the rest of your lives.
If it were accidental, more than likely.. I have a habit of being very critical when I cause harm unintentionally to others. However, if someone where to deliberately put myself or (more so) my loved ones in a predicament to where I felt serious harm or death would occur.. I would flinch, hesitate, or even think.. that person would be dead. I think as humans we all harbor a primitive savage nature of sorts within us, and a fair amount of the population has sufficiently suppressed it through media over-sensitization. However, I recognize that I have the ability to protect myself and others, and know what capabilities are, however savage, in a worst case scenario defending myself or my own.
Be prepared for everything, even if you hope it never has to come to that. Accepting certain ideals before their realization with save you on the shock and possible mental trauma that could follow.