That's probably a mil-surp vehicle that was "given" to the PD for a pittance, plus shipping.

"rescue"........... In the LAPD N. Hollywood shooting, they wounded were evecauated with commandeered(?) armored cars, ie the money trucks. Armored cars could be very useful in getting people out of bad areas. Luckily in LA, would've thunk armored cars would be near a bank, they car companies, or at least the drivers of those particular cars were more concerned about saving lives, than possibly damaging comapny equipment. Seems like a kinda sketchy plan though if you really are counting on a rescue.

Cheif Wiggum Snake is shooting from his cabin and Lou is down in the open...... [Wiggum voice] I've planned for this, all we have to do is flag down the first armored car that goes by.........[/Wiggum voice]

[Kent Brockman] I'm on the scene of a shooting, hopefully the criminal isn't watching this live broadcast.............[/Kent Brockman]

Yes, they also have a waterborne SWAT element.
Rutherford County has an APC and access to more from the local guard unit in Smyrna (LAV's). All LEO agencies in Rutherford ounty has access to this equiptment by picking up the phone and asking.