He most likely was wearing a six point harness.
They fully release with one tug of a lever by the driver.
It’s what kept him safe, and allowed him to get out quickly in case of fire.
I have been informed that whatever harness he had, it came detached from the car floor and that is why he ended up with his legs sticking out of the smashed front window...
He was lucky he did not break something...like his neck..
(bet he secures the harness much better in the future)