"Now we wait," says Goto Dengo, and shuts off his acetylene lamp, leaving them in darkness. "As long as we do not burn lamps, there is enough air in this chamber to keep us alive for several days. Captain Noda and his men will spend at least that long tidying up the Bundok site, erasing all traces of our work, and killing themselves. So we must wait, or else his men will only kill us when we appear on the shores of Lake Yamamoto. I would like to spend the time educating you on the subject of caisson disease, also known as the bends."