Wear shirt w/ tie. Bring your white coat (you will round with a team).
Don't try to arrange a meeting with the PD. The 2nd look is just for you to get a feel for the day to day.. and not to rub elbows with any admin people. That's not to say you won't encounter the PD.. If you do, just say hi, intro yourself and leave it at that. If the PD offers to chit chat, then by all means, otherwise, leave it at that.
That was my experience. It worked out well. Just don't present yourself as overly aggressive. In my mind, you are there to observe and get a sense of what's it like. nothing more.