If you are being chased by guards, and two or more guards try to block off the street by holding up their swords and striking you when you get close enough, there is a way around this. You could simply ignore them and go to another street, or you can do the wall-run. If you time it just right, you can run over to the wall, and go diagnolly into it, and you will do a wall run right over the guards' heads.