The posts here have been very instructive with some fascinating explanations. My take aways:

1) A broken chain is not in itself a big problem but when a chain gets caught and causes the rear wheel to lock up - always bad.
2) Sudden loss of connection between foot and pedal is very bad especially at high speeds

I mostly ride fixed gear bikes on flat surfaces. I use HKK chains which are very strong and Shimano SPD pedals which provide a secure footing. This has been a great reminder of how important and interconnected the entire drive train is.

Tomm let us know how your recovery goes. We're wishing you the best!