There's probably a city lawyer combing through the law, trying to find some legal theory to hold the van owner responsible for the gunfire, the bullet holes in the police car's windshield, damage to the officer's hearing, and the cost of the rounds expended.
After all, it's not their fault that they opened fire on a backfiring van . . . it could have been an attack.
And they got to go home at the end of the shift.
(Did I need to include the [sarcasm][/sarcasm] brackets?)