But he wasted no time with such thoughts. They ran, all three, into the dark tunnel.
Quade caught up with them quickly. Personal enmity was suspended before this common peril. They could not run at full speed, for a multitude of obstacles hindered them. Tortuous ridges of rock lay directly across their path, formations that had been whipped in some mad, eon-old convulsion and then, through the ages, remained frozen into their present distortion; black pits gaped suddenly before them; half-seen stalagmites, whose crystalline edges were razor-sharp, tore through to their flesh. Haste was perilous where every moment they might stumble into an unseen cleft and go pitching into awful depths below. They were staking everything on the draft that blew steadily in their faces; Phil told himself desperately that it must lead to some opening—it must!
But what if the opening were a vertical, impassable tunnel? He would not think of that....
Old David Guinness tired fast, and was already lagging in the rear when Quade gasped hoarsely:
"Hurry! It's close behind!"
urging rapidly at a constant distance behind them, it came on. It was as fast as they were, and evidently untiring. It was in its own element; obstacles meant nothing to it. It oozed over the jagged ridges that took the humans precious moments to scramble past, and the speed of its weird progress seemed to increase as theirs faltered. It was a heartless mass driven inexorably by primal instinct towards the food that lay ahead. The dim phosphorescent illumination tinged its flabby tissues a weird white.
The passage they stumbled through narrowed. Long irregular spears of stalactites hung from the unseen ceiling; others, the drippings of ages, pronged up from the floor, shredding their clothes as they jarred into them. One moment they were clambering up-hill, slipping on the damp rock; the next they were sliding down into unprobed darkness, reckless of where they would land. They were aware only that the water-odorous draft was still in their faces, and the hungry mound of flesh behind....
"I can't last much longer!" old Guinness's winded voice gasped. "Best leave me behind. I—I might delay it!"