The fight or flight exists in the limbic system, according to my still very rudimentary neuroanatomical knowledge. The freeze is in the brain stem, as is the shit your pants and go out of body. I think that is right, although freeze may be limbic too.
But all of these are REACTIONS to violence and danger. What is going through the head of the mountain lion stalking an unaware goat? There is likely something like adrenaline,but it is focused, clear. Their figurative hands are steady, their focus intense, but whatever fear there may be is channeled into awareness and attention.
I think I read somewhere that predators don’t get the shakes like prey do. They don’t get the animal equivalent of PTSD which they then have to literally shake off.
Is there a predator instinct, which combines elements of all three levels of the human brain, and which is exemplified by people with “killer instincts”?