They dropped down several levels, passing off-shoots of the main shaft (shut your mouth!... I'm just talking about... yes I know it's an old, old joke, but nothing amusing has happened for the last dozen posts and I'm getting antsy.)<br/><br/>Suddenly, Ptricia called up, "Whoa! Hold your horses!" At the base of the shaft was a horizontal rotating fan. Somebody had clearly saved on constuction costs by not putting a grill on the upper side, as in the side they were currently sliding down towards. Ample evidence that the blades were sharper than aerodynamically necessary was the ac that the tail end of the thread they'd been sliding down had been neatly sliced off as it hit the fan.<br/><br/>(And beyond, a secret control room? Secret laboratory? Secret mess hall? But first our heroes have to avoid becoming salami.)