Roger almost answered. Almost. What he saw ahead, though...

He held up one fist in the 'everybody stop now' gesture he'd used in the Army, and froze. His helmet lamp, and to a lesser degree Sirius' wand, cast a faint glow into an enormous, faintly green-litten chamber. Pairs of pillars thick as a man, carved all over with snakes and serpentine designs, stretched away into the gloom. The whole place had an air of chill, of gloom and shadow, and frankly, he didn't like the sight of it one bit.

He reached over his shoulder for the laser rifle, just in case.