Now return to the doorway and pull up onto the ledge where you just opened the gate. Head for the left side of the platform, avoiding the glass shards. Turn and face the lowest point of the crevice in the brick wall. Do a running jump to grab this crack, then traverse to the left until you can pull up. Flip the switch here to lower the drawbridge and cue the ominous music. Drop to the floor, return to the doorway and pull up to the platform with the broken glass again.