Quicksand is total bullshit, a fabrication, perpetuated by Hollywood until about fifty years ago.
Come on, fess up - some of you didn't know this.
Pssst ... don't feel bad ... I didn't know either.
The truth is that, most likely, nobody in the history of the world has ever died in quicksand (underwater is an exception because you can drown, and I suppose if you were an unfortunate skydiver, and landed head-first, you'd be pretty much hosed).
Jun 15, 2002: "Where Has All the Quicksand Gone?" on boryssnorc.com
Oct 7, 2002: "What is Quicksand" by Darrel G.F. Long on scientificamerican.com
Sep 29, 2005: "Quicksand Myth Exposed" by Patricia Reaney on abc.net.au
The "shortcut" way to look at this is: Quicksand is about twice as dense as the human body, so you can only sink about halfway down before stopping, and you couldn't become submerged even if you tried.
This is about as close as you come to dying: