The Hall of Deception is a small sized instance. The iron tablet will reward 6000XP after killing the boss. Before you can enter the Hall of Deception you have to travel through the Secret Passage. If you are here for the Celestial Painting for the Statues quest, you will not be able to dig it before the party of three tough Skelezans (mummified skeleton types) wanders down the ramp and attacks.