As I understand it, killer "instinct" is already there. As another poster put it, it's suppressed from childhood. The urge to defend and protect is natural. Thinking back to when I was child, I can clearly remember getting very upset when I thought a person was treating a family member wrong. My older brother and older sister tell me stories of how I'd get red, start breathing heavy, start sweating and start walking forwards. After I'd 'calm' down, the shakes would start. Sounds like an adrenaline dump. Fight or flight. Looking at my neices and nephews, I sometimes see the same thing. Another child pushes a sibling and the "Don't do that to my..." starts up. We then say "It's okay, calm down" and because it's the 'right' thing to do, suppress that instinct.
I think the question was how many of us have the killer instinct. For me personally, I ask myself if I have that killer mindset. In my mind, that means if things go right, I walk away with my family and he doesn't... and if things don't go right, I don't walk away with my family and neither does he. And if\when I do allow myself to fall into that state of mind, do I have it within me to gear it down if the situation changes.
Rick R.
UKF Campbell, Ca.