See through walls, walk through walls, run at 200%+ speed fulltime, get an enemy-populated map of the area, etc could all be used to significantly shorten the amount of time it takes to clear any given floor.
Most of the talk on BG about this is generally more along the vein of "God dammit, I do not want any event where I have to use X, Y, Z to win it. This is screwed up."