Remember back to the area just before you entered the building to go onto the roof, there was a bridge hidden offscreen to the left that leads to another area. Once you cross the bridge there is a giant crossbow to the left, drag it into the next room which is straight once you make the left. Once you are in the room there is a symbol on the floor by a door you can lift, place the crossbow ontop of it. Open the door, but beware because you will then get attacked by several undead. After defeating the undead, you will see a lever in the room. Pull the lever to turn the crossbow 90 degrees. Remove crossbow, and pull lever again. Replace the crossbow and again pull the lever, this will turn the crossbow so that you can shoot a breakable wall. Investigate the other liftable doors to find breakables with red orbs. Also, a ladder apears when you pull the lever, climb up to find more red orbs. After breaking thru the wall with the crossbow contenue to a big room where you will encounter Zeus and be enchanted with his power to throw lightning bolts. Exit the room and kill archers on roof outside of Zeus' room to open a secret room full of red orbs. Return to the roof and defeat the archers with your new power. Then you will encounter a coward who will not release the bridge for you to cross, use your new power to deal with this problem.