Between him and the stairway stood still another fortified door, heavier than the others. He did not stop to knead his paste, for already he could hear the crash of glass and the sound of sledges on the door at the rear of the cigar-shop. Catching up a strand of what he knew to be the most explosive of all guncottons—it was cellulose-hexanitrate—he worked it gently into the open keyhole and again scuttled back to safety as the fuse burnt down.
He could feel the building shake with the tremor of the detonation, shake and quiver like a ship pounded by strong head seas. A remote window splintered and crashed to the floor, sucked in by the atmospheric inrush following the explosion-vacuum. He noticed, too, as he mounted the narrow stairs before him, that he was bleeding at the nose. But this, he told himself, was no time for resting. For at the head of the second stairway still another sheet of armored steel blocked his passage, and still again the hurried, hollow detonation shook the building. The ache in his head, behind and above the eyes, became almost unbearable; his stomach revolted at the poisonous gases through which he was groping. But he did not stop.
As he twisted and pried with his steel lever at the lock of the trapdoor that stood between him and the open air of the housetop, he could already hear the telltale splintering of wood and sharp orders and muffled cries and the approaching, quick tramping of feet. He fought at the lock like a madman, for by this time the trampling feet were mounting the upper stairs, and doors were being battered and wrenched from their hinges. He had at least made their work easy for them; he had torn open the heart of Penfield's stronghold; he had blazed a path for those officers of the law who had bowed before the inaccessibility of the building he had disrupted single-handed!
"Good!" he cried, in his frenzied delight. "Give it to them good! Wreck 'em, once for all; put 'em out of business!"
Then he gave a sudden relieving "Ah!"—for the sullen wood had surrendered its bolts, and the door swung open to his upward push. The night wind, cold and damp and clean, swept his hot and grimy face as he pulled himself up through the opening.
Even as he did so he heard the gathering sounds below him growing clearer and clearer. He squatted low in the darkness, and with a furtive eye ever on the dismantled trapdoor, groped his way, gorilla-like, closer and closer to the wall against which he knew the janitor's ladder to be still leaning.
Then he dropped flat on his face, and wormed his way toward the nearest chimney, not twelve feet from him, for a wet helmet had emerged from the trap opening. A moment later a lantern was flashing and playing about the rainy roof.
"We've got 'em! Quick, Lanigan; we've got 'em!" cried the helmeted head exultantly, from the trapdoor, to someone below.
The next moment Durkin, prone on his face, heard the crack of a revolver and the impact of the ball as it ricochetted from the roof-tin, not a yard from his feet.
He no longer tried to conceal himself, but, rolling and tumbling toward the eave-cornice, let himself over, and hung and clung there by his hands, while a second ball whistled over him.