Wow! If something like that happened to me, I'd be pretty shook
up.
I'm curious to know how/why it happened, though. The hoods of most
cars are double latched, i.e., even after pulling the release lever
or pressing a button inside the cabin to "pop the hood," one still
needs to manually disengage a second latch usually located under
the front lip of the hood, before the hood can be raised.
Even if the hood had been popped from inside the cabin, the second
latch should still have prevented the hood from flying open.
But with GM engineering and quality control being what it is,
anything's possible. 
