Did I just watch someone die?
It seems likely. That vehicle was just swallowed by a flooding river. It’s technically possible the occupants escaped, but unlikely.
It’s not easy for people to escape a submerged vehicle in still body of water, especially if the vehicle flips. Add in a raging river tumbling everything around, pushing everywhere… Even if you were able to escape the vehicle I don’t think your chances of making it to shore from the middle would be good.
According to this the driver survived:
https://news.sky.com/story/truck-driver-takes-on-flooded-suspension-bridge-and-loses-12362557
Happened in the village of Uryum in Eastern Russia.
probable location in google maps: https://www.google.com/maps/place/53°10’09.1"N+118°07’00.0"E/@53.1675162,118.1063825,2661m/data=!3m1!1e3!4m4!3m3!8m2!3d53.1691944!4d118.1166667?entry=ttu
River is the Shilka river, a branch of the Amur river.