Sleep deprivation in itself might not be fatal, but its consequence is too often fatal. We lost a SAR team member a number of years ago for this very reason due to lack of sleep at a search. As she drove home, without the benefit of a nap, fell asleep at the wheel and struck a tree. Following that the team instituted new dispatch policies to prevent this in the future.

We always stress following a long field exercise or mission, to rest and/or sleep before driving home. The drive home can be the most dangerous phase of a mission. Once the adrenaline wears off during the return trip, it's quite easy to fall asleep.