The inside of the tower is cobbled with cracked granite, upon which are four goblin bodies, apparently slain in combat. One corpse stands with her back to the wall, the spear that killed her pinning her upright. Three wooden doors lead from this area (this includes the one you opened). The hollow tower of loose masonry reaches thirty feet into the air, but the intervening floors and stairs are gone, except for a few crumbled ledges.