Is a police station a no firearms zone ? I wonder if it was expected that Waller would be unarmed by Childress. The guy had to be doing some heavy thinking as he chased Waller through town. He must have known Waller carried a gun (via the woman in center stage in this scenario). I think Waller must have had his gun in his hand when he got out of his car, as the shooting took place very quickly. In California one is expected to take a beatdown before resorting to lethal force.
When the number of people in institutions reaches 51%, we change sides.