A lot can happen in the space of a breath...
He falls into a shooting stance, lines up the sights.
Exhale.
He squeezes the trigger.
A life disappears in a spray of blood.
His heart beats again, a smile on his lips so brief it's never seen.
In that brief instant, he's filled with a satisfaction and a pleasure so intense it's terrifying. He's harbinger of death, angel of justice, beholder of absolute power.
Inhale.
Quick sadness invades him with the reality and absolute finality of what he had to do, again. He quashes it.
It's his job.
He's good at it
And so god help him, he loves it.