His job is not to press the button. When he fails at his job, people don't die.
There used to be support groups for people like him, groups he wasn't supposed to attend but did anyway. They were for the people who worked the most awful images the human mind could conceive, videos of violence and sexual abuse beyond any quaint nightmares they might have had before, flagging them so the psychological damage of seeing those videos — and knowing those things were happening at that very moment to some terrified person inarticulate with pain — would remain contained inside their own minds. They could barely afford food on gig economy rates, much less therapy, so they met online to not talk about what they couldn't, and half-heatedly and not often successfully prevent each other from killing themselves.
He would go to those groups to seek some simulacrum of health in their shared illness, yet there would always be a barrier between him and everybody else. What he sees every day isn't the crisp video of a carefully recorded personal hell, but the blurry real-time monitoring feed of a superhumanly fast combat robot moving, targeting, and shooting quicker than any human could. It would be impossible for him to decide faster and better than the robot which of the moving figures are enemy combatants, children trying to run from a war without fronts, or both.
So he never presses the button, and prays every night beyond statistical hope to have never let a terrified innocent die.
The groups went away when computers became better than humans at filtering out that kind of material, but he knows he will never be replaced. No matter how good the robots get, how superhumanly quick and accurate their autonomous reactions, there'll still be innocents dead whenever they are used for what they were built for; not because the technology is flawed, but because that's the tactically optimal tradeoff they've been configured for. His job is to take the blame for, and only a human can do that.
He doesn't drink, nor take pills, nor beat his wife. He has no dangerous hobbies. He does his duty like any good soldier would do.
In his dreams he seems himself on a screen, his face framed by a targeting solution. The image stays stills for an impossibly long time, yet he never presses the button.