I can't make this stuff up.

Have not driven the SRT for a few months for different reasons and decided to work on it today. Everything is going well but as I was doing a test drive I heard a clicking from the back like a nail in the tire. As I am taking the rear wheel off a lug snaps (appeared to be loose beforehand as if about to break). As I am beginning to extract the broken lug it actually pushes through the hole and appears to be behind the rotor somewhere. There is a plate or something back there too and I can't see a way to get in there to get the broken piece. I hope I explained it well enough. Any ideas? Do I have to remove the rotor? Thanks