What does an enemy do when no unoccupied path lets it reach a hex to attack an adventurer?

Question

Accepted Answer

If no valid destination hex exists, the enemy moves toward the closest opposing unit. That unit may be a stealthed adventurer, but the enemy still cannot attack it unless it started adjacent to it.

The Elder Scrolls: Betrayal of the Second Era

What does an enemy do when no unoccupied path lets it reach a hex to attack an adventurer?