I believe you already have an audio for it on your 3 position selector switch.
As for your 'Police Elephant, I'm sure I saw a film, Possibly with Dan Akroyd as one of the 'stars', where they busted into a building with a light tank, painted Police dark Blue with white 'Police'. On the end of the barrel was a sign saying something like NY POLICE.
There's lots to play with on that theme, your Local Canadian or RCMP scheme;, US ATF, Sheriff's Dept, SWAT schemes. The world is your Oyster.
Its YOUR MODEL, do what you want with it.




