By golly, you're right! GOOD EYE, LUCKY!!! It's a rectangular shaped sheet..and NOW it's easy to see it kinda lying across the manhole (1/2 on it & 1/2 off) immediately at the start of the vid.
I didn't notice the darn thing.
'Guess I had good reason, then, to assume that the wreck couldn't have happened with the manhole cover IN PLACE, huh! :lol