Two points occur to me:
"Shoot-to-Kill-Policy" never been anything else. No such thing these days as "warning shots" or disabling shots. If you have to shoot (very big IF) then you shoot to kill.
Head Shot or Not Normally a body shot - apart from anything else it's a bigger target. But (very big BUT) death is not as instantaneous as a head shot. Might not be time for the full John Wayne life-story-and-look-after-the-kids dit, but enough time to press a button in yer pocket. And that's before you consider whether a "lucky" shot might set off the det.
No time for button=instant death=brain death=head shot.
QED
Once again - well done to SO19 or whoever.