Stop in for a cup of coffee

I pulled into a police station to make a delivery. I set the brake because the battery was weak and wouldn't start the truck. I was standing there telling the chief that I had his order of road signs when there was this big crash! The brake was not set properly and the truck rolled down the hill right through the garage door and hit the new cruiser that was being prepped with the radio and other equipment. And I did not get fired!
And the subliminal message was?