I bought Fairfax's Castle and am stuck in a tomb where I have to shoot at a floating orb to get through a sealed doorway. It requires me to shoot the orb to a stone slot, but every-time I shoot at it the orb deflects to the opposite side, even as I can sometimes hit it 2nd time, but and I'm back to square 1. How do I get it to go where it needs to go as I can't leave the place as it says I will loose what I've done already and never return?