Back when I was in college, I had a job at a tubing and canoeing place on the Delaware river. One part of my job was hopping in a canoe and paddling upriver to chase paying customers off the water and back up to the road for bus retrieval, whenever a serious unexpected thunderstorm rolled through. So, I'd be out there in the middle of the river, paddling my heart out, and wondering why it was safe for me to be there if everyone else is supposed to get off the water.
These guys must be thinking about the same thing. "You say there's a sink hole? You say you want me to go stand there and prop up the tracks? It just happened, and no one knows the extent of subterranean erosion, yet? Uh, I'm not feeling well today, I'd better go back to bed."