Yeah, dude; I'm a big martial arts nerd. The cop class will be awareness training and how to not put yourself into a victim position. If it involves fighting, it's going to be subduals, grabs and holds.
Most reality-based systems will teach you enough to move around and avoid shots. I once evaded three aggressive would-be attackers in a parking lot using basic boxing footwork and duck and weave. Unless you box, you aren't going to hit a boxer who doesn't want to be hit, so I would say boxing.
In fact, boxing, kickboxing or something like Jiu Jitsu might be perfect for you.
If you want to dismantle a human being, consider Kali, Escrima or Arnis (if you can find it).
But the real thing to do is look at what you actually have avaliable in your area, and choose from that list based on what seems the most fun. Because fun is the thing that keeps you coming back.