Lucian goes ahead, while the rest search behind him.
You come to stairs going south. After about 20 feet of stairs, the tunnel turns back east. After another 15 feet or so, you see a big pit. There is nothing subtle about it. It covers the 10' width of the hall. 10' deep, it fills 30 feet of the hall. Its floor is a mass of wide-set rusted iron spikes.