yeah... save up all of your experience potions, and build up physical shield... buy a lot of will potions... then go to the prison path and fight all of the undead that keep spawning with your shield equipped until you have a massive combat multiplier... then take the experience potions...
the combat multiplier multiplies during combat...
you have to fight them...
... just standing there will just eliminate your shield and eventually get you killed...
you do know that you are supposed to kill enemies to gain experience, right?