Payola

Went to the Equalizer, a really shitty movie.  The low point came when Denzil Washington, who is neither Edward Woodward nor his bootlace, had an extended killout in a Home Depot hardware warehouse, offing the villains with barbed wire nooses, pruning saws (I think), and - for god's sakes - battery-operated power drills to the head.
You cannot kill a person with a power drill to the head unless they're held down against a wall or floor. Even if they don't move of their own accord, which seems unlikely, the drill just push them away. It will spin off the skull without penetrating, and if it doesn't it will still take some time - seconds - to get through the skull to the brain, allowing them to avoid death by stepping away. You'd be better off hitting them over the head with it.
You'd also be lucky to have a barbed wire spur pierce a vein, and you can't shoot someone at a distance with a nailgun.