Oh dear! But unless you're as strong as a horse, or were using a crowbar to get your bike out, the clamp was already broken and just needed the extra leverage to fall off.
So you were lucky! It happened in a safe place and not on the trail causing you to endo 
Derailleurs however do not like being caught in car doors or stuck under luggage, and can bend fairly easily.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett