They couldn't resist having a situation where Brandon DeWilde has it in the script to call out, "Come back!". Like he did, as a child actor, in the movie"Shane".
Of course, quick-sand, or it's equivalent. Is a pure Hollywood invention. Used (overused really) to create a fake life or death situation in many old movies and TV shows. Surprising, it took almost 4 full seasons for COMBAT! to resort to this hack script idea, but they did!