They did.
The guys at the Corral Springs police department that they had been training with knew they were there.
Or do you mean they should have called up their boss in Miami.
"Hey captain, there is a active school shooting going on. Should we help or just sit here playing with ourselves like you do?"
Actually yes. They have a duty to notify their command where they are headed to. It’s a 10 second call over the radio or cell. They needed to let Miramar PD know they were responding. You can’t just freelance, it’ll be chaos.