When Al Mualim gets ready for the final part of the battle immediately after his third
speech, lock on to him and equip your hidden blade. Move closer to him and when he is 
ready to attack, counter him to score an instant kill. He will fall to the ground and 
you can easily assassinate him without chasing him all over the courtyard. However, 
only do this if you have mastered the use of your counter attacks.