They reach the end of the drift, where another narrow shaft pierces the ceiling. A fat reinforced hose runs up into it, compressed air keening out through tiny leaks. The sound of drills can be heard, from very far away. "I would not recommend that you look up this shaft, because stray rocks occasionally come down from where we are working," he warns. "But if you looked straight up, you would see that, about ten meters above us, this shaft comes up into the floor of a narrow inclined shaft that goes uphill that way—" he motions northwest "—towards the lake, and downhill that way—" He turns a hundred and eighty degrees, back towards the vault.