The Symbolic Significance of the Earth "Opening Her Mouth"

Why were Datan and Aviram swallowed by the earth? Perhaps this was a direct reciprocation for their actions: they didn't want to ascent to the Promised Land, and they ended up descending to Sheol; They called Egypt "Land of milk and honey," and Canaan "A land which eats its inhabitants," and ended up being eaten by the land upon which they stood.