Apparently when Mark Cavendish crosses the line in one of those 40+mph sprint wins and throws his hands in the air, he inadvertently whips his cranks backwards and pops the chain off.

that's pretty neat.
did that happen at one of his two recent stage wins?
I've never heard commentators mention this before with sprint finishes, but that certainly doesn't mean it doesn't happen.
PS looked up and read some stuff about these incidents.
yup, pretty neat and curious combination of quick events doing this.