if its anything like humvees you could learn how to do basic maintenance and operations on one in an hour
Maybe for something like that, sure. But an MRAP is fairly unique in that it's forgetin heavy as stuff, you sit really high up, and you can't see very well out of it.
It would be a loving MESS if someone were to be accidentally run over with one of these things. That isn't a risk you want to take in a sensitive situation (for example, a riot or protest which can easily explode in into violence). I'll admit that I don't know too much about these vehicles, but (and don't laugh too much) I can't see stuff out of the Arma 3 MRAP. That thing is based on the M-ATV, which is very similar to the one in the picture, except the MATV has BETTER visibility.
That's basically why I think that having these are a bad idea. It's a potential liability unless you have it on good authority that you're gonna be driving around landmines and RPGs. Maybe a Humvee or a similar militarized vehicle would fit the role better, being that they're more durable than a standard cop car and have a similar intimidating effect.