F.1C and A10.51?
When desert boards are in play (F) units are eliminated for failure to rout only if within 6MF of an enemy unit, and units are not required to rout toward Building/Woods that it cannot reach in that rout phase. (consistent with A10.51)
So for a desert board any unit can low crawl in 'direction of choice' if no building or woods hex is within 6MF as long as not moving toward an enemy unit.