I was told once that a sniper will aim for a spot just below the nose and that will shut off a man like a light switch.
Then you were told by a person who enjoys blatant over-simplification or has an amazingly poor understanding of terminal ballistics.
That magical spot below the nose could be cut out with a knife, hit with a fist, or shot from the side and not produce the desired result. Why? It isn't the spot under the nose that is relevant.
The magic spot under the nose is meant as an aim point to produce a shot that will strike the top of the spinal chord or bottom of the brain stem. For this to happen, the shot needs to be impacting level or with a slight downward angle and needs to shot from a location where the target is oriented such that there is perfect alignment between the sniper bullet's path, that magic spot, and the brain stem or spinal chord. Note the that target has to be completely vertical, right side up or down, for this to happen. If the target is leaning to any side, the impact location needed to produce the brain stem/spinal chord shot will have to change. Upon striking the magic spot under the nose, the bullet's will need to remain true and not alter course as it passes through skin, the premaxilla, maxialla, pallate, soft pallate and other connective tissue before passing through the sphenoid to impact the brain stem or below to the spenoid to pass through the atlas or axis vertebrae to hit the top of the spinal chord.
How would this be accomplished to get the correct direction of penetration from the spot under the nose to his the lower brain stem/upper spinal chord? The shot w ould need to be a close range shot with a flat trajectory or a long range shot where the shooter is on a lower plane than the target's spot belong the nose such that as the bullet arcs through its trajectory it would enter and pass straight back as would happen with a close range flat trajectory shot.
Could this happen? Sure, but it is remarkably difficult to aim at an exterior feature with hopes that it will then impact the necessary internal small structure after passing through various types of hard and soft tissue and not be deflected off course.