A new rule was added the other year, 'Terror'.
Terror in the old rules meant you stayed rooted to the spot for about 10 seconds, then ran away as per the fear effect.
Terror disappeared with the move to v3, where fear is 'run until you're 10ft/3m away and stay at least that far away for 10 seconds'. The new, introduced in 2009, Terror is exactly the same, but affects people who're immune to fear effects (which is a very common additional skill).