The Hole Paradox.
Generally, the deeper the hole (fighting position, foxhole, slit trench, whatever) the safer; and, the quicker you take cover, the safer.
The paradox is that the deeper the hole the more likely it is you will be injured getting into it, and that likelihood is multiplied when troops start trying to dive in.
Always a bummer when the rockets stop and someone's in a hole with a busted neck or collarbone.