I've had something like this happen 3 times. I've had no mechanical problems since I started riding fixed, but for some reason within a week I threw my chain or had it snap 3 times on 2 different bikes. One was my spectacular crank failure, the other was my masterlink shattering after going over a bump, and the last was my hub threads stripping and a few of my chainring teeth getting sheared off. All 3 times I took my left foot and jammed it on the top of my back tire coming to a controlled stop. My shoes are almost burned right through though now and it sucks because they were brand new! At least I still have my health!