I have never wandered into this nasty stuff but had always thought you can “swim” your way out of it.
Apparently it’s not that simple.
Note that they’re doing this while the tide is out. What if it were coming back in and he was all alone?
Scary thought. So is the fact that this quicksand looks exactly like the solid mud.
Bottom line: ALWAYS pay attention to your surroundings, and if you see warning signs, heed them.
On a reassuring note, reportedly wet quicksand isn’t a bottomless pit. So you might not not sink in all the way.
Per Wikipedia, density differences are a factor, too.
Featured image: Urban Dispute, CC BY-ND 2.0.