Pratt hesitated no longer. The men were evidently making for the ruins: perhaps they intended to proceed along the tunnel. It was imperative that he should anticipate them. He hastened downstairs, and had just reached the cellar when he heard clumping footsteps overhead. Leaping into the cavity, he swung the stone over, turned the hand-grips, and by the light of the torch bolted along the tunnel. After running about twenty yards he switched off the light and stopped. Voices came from behind him; then he heard two heavy thuds in succession; the men had jumped into the tunnel. The flagstone banged as it was swung carelessly into place; the men were coming after him. Without more delay he set forward with all speed, guiding himself by touching the walls with his outstretched hands.
Meanwhile, what had happened to Warrender?
On entering the cottage by way of the tunnel and the cellar, he went upstairs to make a careful survey of the surroundings, saw no sign of the enemy, and hurried across the island to the pram, in which he crossed the river unobserved. In less than ten minutes he was back at the cottage with the hammer and chisel taken from his motor-boat. As he was on the point of re-opening the trap, he found that the electric torch showed a much feebler light than before, and if it gave out before Mr. Pratt was brought away, the flight through the tunnel might be dangerously delayed. It seemed worth while to pay another rapid visit to the camp for the purpose of getting a small hand lamp or a couple of candles. Laying the hammer and chisel under the staircase, he went up again, once more crossed the island, found one candle in the motorboat, and returned without delay.
It happened, however, that as he left the cottage on this second journey, Rush and his big flat-faced companion were approaching it from the south. Unseen themselves, they caught sight of Warrender as he emerged from the entrance, watched him until he had disappeared into the thicket, waited a few minutes, then entered the cottage and descended to the cellar. They had no light, and Warrender had taken the precaution of carefully replacing the flagstone; but in his haste he had omitted to close the upright slab beneath the lowest step, leaving open the access to the handgrips. Rush was suspicious. The gap might have been left open, of course, by one of the confederates; on the other hand, it was possible that the secret passage had been discovered by the boy he had seen leaving the cottage. The boy might return, and Rush allowed his curiosity to delay the visit to the tower on which he had been summoned. It was an error of judgment that had important consequences.