She was also a pathlogical liar -- and mental game player, seems I'm kind of immune to that stuff, can see through the lies and just don't give a fly's tush for mental games. All which she knew, so she hung with me for psychic relief on her part. Didn't stop her from trying to get me involved in the myriad of risky schemes that she was constantly coming up with. For the most part, they rolled off like water over wax.
Anyway, she's the kind of woman I could picture doing that kind of thing -- shooting a boy at random on some whimsy. I mean I knew another woman, also a mighty deer hunter, who read books about serial killers during lunch, yet she could never do such a thing, imo -- she just wasn't a liar.
Inveterate liars have that mental displacemnt to do such a thing --once -- but even they couldn't pull it off again and again -- imo. To repeat -- you have to be trained or crazy, and craziness if so acted on is a quickly accelerating spiral out of any control.
So, I think this terror sniper is someone who has trained him/herself well and long, or who has been trained.