This is one of the hazards of being an archaeologist (it has happened to me a few times) but it is sad to see it occur with a private citizen.
The moral of the story? Don't be talking on your cell phone when instead, you should be scanning the terrain in front of you with Ground Penetrating Radar to locate cavities that are too close to the surface.
Aie! That was horrifying! So after I watched it three or four times... Now I'll probably walk into a light post or fire hydrant while I'm watching the ground to make sure it doesn't eat me.
Just keep a horizontal bamboo poll attached to yourself.
"weak section of pavement"? The alleged pavement was paper-thin at that spot; the contractors sure scammed the government on that one. Or was it a case of a garbage bag placed across an open manhole?