Officers aren’t just told about the risks they face. They are shown painfully vivid, heart-wrenching dash-cam footage of officers being beaten, disarmed, or gunned down after a moment of inattention or hesitation. They are told that the primary culprit isn’t the felon on the video, it is the officer’s lack of vigilance. And as they listen to the fallen officer’s last, desperate radio calls for help, every cop in the room is thinking exactly the same thing: “I won’t ever let that happen to me.” That’s the point of the training.

More pointed lessons come in the form of hands-on exercises. One common scenario teaches officers that a suspect leaning into a car can pull out a gun and shoot at officers before they can react. Another teaches that even when an officer are pointing a gun at a suspect whose back is turned, the suspect can spin around and fire first. Yet another teaches that a knife-carrying suspect standing 20 feet away can run up to an officer and start stabbing before the officer can get their gun out of the holster. There are countless variations, but the lessons are the same: Hesitation can be fatal. So officers are trained to shoot before a threat is fully realized, to not wait until the last minute because the last minute may be too late.

But what about the consequences of a mistake? After all, that dark object in the suspect’s hands could be a wallet, not a gun. The occasional training scenario may even make that point. But officers are taught that the risks of mistake are less—far less—than the risks of hesitation. A common phrase among cops pretty much sums it up: “Better to be judged by twelve than carried by six.”

In most police shootings, officers don’t shoot out of anger or frustration or hatred. They shoot because they are afraid. And they are afraid because they are constantly barraged with the message that that they should be afraid, that their survival depends on it. Not only do officers hear it in formal training, they also hear it informally from supervisors and older officers. They talk about it with their peers. They see it on police forums and law enforcement publications. For example, three of the four stories mentioned on the cover of this month’s Police Magazine are about dealing with threats to officer safety.

Officers’ actions are grounded in their expectations, and they are taught to expect the worst. The officers who shot John Crawford may have honestly believed that he was raising his rifle to a shooting position even though security camera footage shows him on the phone, casually swinging the BB gun back and forth. The same may be true of the Phoenix officer who shot an unarmed man because he thought, mistakenly, that the suspect had a gun in his waistband. The officers saw what they were afraid of. They saw what they were trained to see. And they did what they had been taught to do. That’s the problem.