The room contained display cases of mineral specimens. There were sulfur crystals, raw emeralds, and rubies. There was a monolith of unpolished pink quartz in the center of the room, three meters wide and six tall.
...
	“Quick,” the Master Chief said. He slung his rifle and moved to the back of the quartz monolith. “Push!”
	Kelly and Fred leaned their weight against the stone and grunted with effort. The slab moved a tiny bit.
	James sprinted forward, slammed into the stone, put his shoulder alongside theirs … and pushed. His left arm had been burned away from the elbow down, but he didn’t even whimper.
	The monolith moved; it inched toward the hole … then tilted and went over. It landed with a dull thud and a crunching noise.