Is it correct to say that the video looks far worse than it actually is ?

As in, the dust/mud particles sprayed & floating in the air do not have the force to do harm beyond vision or breathing impairment, similar to the dust from a collapsing building, or the lead shockwave of a nuclear bomb detonation.

Of course, it looks terrible, and certainly somethingbut its not a reason to perish as long as you can stay away from the following water wall and mud current that does strike sometime after.

No, that's not correct.

The length of time between the spray you mention, and the impact of the water wall, is single digit seconds. It doesn't make a difference.