“Wait!” was all he told her.
He used his key at the other end to admit them to another corridor, much wider, with doors on either side. “X” thought he recognized this as the corridor along which was the door of Tyler’s cell.
He opened the second door on the left and, sure enough, there was the grisly sight of the man who had been the victim of the Skull’s fiendish ingenuity. It was this room that Betty had been made to look into through the barred aperture in the “execution room.”
Tyler was no longer chained. No needle had sprung from the knob though “X” had taken the precaution to stand at one side, and to keep Betty behind him as he turned the knob. Evidently events had been moving too fast even for the Skull since last night, and he had not had time to replace the needle. But when the door opened a bell began to ring, the same as last night. The alarm was given once more, and the Skull now knew which corridor they were in.
Tyler looked up at them inanely, without the slightest sign of intelligence in his eyes. His hands were shaking as if from palsy, and his lower jaw hung slack, as if out of his control, allowing saliva to dribble down to his chin.
Betty uttered a horrified gasp, leaned against the wall for support.
“X” stepped into the room, gripped Tyler by the arm. “Come on,” he said in a gentle voice. “I’ll take you out of here.”
But Tyler shrank back, uttering an incoherent sound that was between a scream and a moan.
Suddenly the hidden amplifier in the corridors came to life once more, echoing the voice of the Skull. “Fannon is now in corridor H, in Tyler’s cell. Every one is to converge on corridor H. Do not let him escape again. Converge on corridor H!”
AT the same moment a panel high up in the wall began to slide up, revealing the same barred aperture through which Betty had been forced to look. As the opening, at first narrow, began to widen, “X” could see the bright light of the powerful spotlight in the execution room focused on it. Once that opening got wide enough, he would be bathed in its rays, helpless against the Skull who was undoubtedly still there.
Shrugging, he relinquished his grip on Tyler, slipped out of the room, and slammed the door. In the corridor Betty was still leaning weakly against the wall. “How terrible!” she murmured. “That man must be destroyed before he does the same thing to more people.”
“He will be,” the Secret Agent assured her grimly. “Now let’s worry about ourselves.”
He led the way along the corridor, just as the amplifier announced, “Fools! Can’t you find corridor H? Binks has not returned yet. You must find it yourselves. Fannon cannot escape; he must be found and killed; the girl, too.”
Betty asked tremulously, “Is there no way out?”
“X” had taken a peculiar, boxlike contraption from his pocket; this was no larger than a package of cigarettes, but it had a hole at either end, in which, Betty could see, there were lenses. He now stooped and removed the framework that had fitted under the sole of his shoe, and which he had worn on the way in with Gilly and Binks. He placed this in his pocket, and examined the floor as they went along. They worked their way through two more passages, and came to an elevator without encountering anybody. As they went down in the elevator, Betty asked, “What is that box — a camera?”
He smiled. “No, but it is the instrument of our salvation. It is a box containing a specially angled series of lenses which I built myself. It is constructed in accordance with a little known theory of light refraction, and shows markings invisible to the naked eye.
The elevator stopped, and they came out into another corridor.
“X” stooped and looked through the lens, then allowed Betty to do so. She saw faint scraping marks on the floor.
“This is one of the passages through which I entered with Binks. I wore a short piece of gray graphite attached to the sole of my shoe when I came in, and particles of the graphite detached themselves as I walked. By following them we will get out!”
She looked up at him, suddenly smiling, suddenly hopeful. “And then?”
“And then,” he told her grimly, “I must begin all over again — work my way once more into the ranks of the Servants of the Skull. He must be destroyed!”
They were now following the particles of graphite through a damp tunnel that gave every evidence of being far below the surface of the ground. This was not one of the elaborately constructed passages, but evidently the outlet of route number seven, that by which Binks had brought him and Gilly in. The amplifier did not reach here, but far behind them they could still hear its metallic tones, hear confused shouts as men scurried around in search of them.
This tunnel led them at last into a small room without windows. There was a door at the opposite end which “X” tried, but found locked. There was no light here, but “X” used his thin pocket flash.
Betty waited while he brought out the kit of chromium steel tools which he had taken from the bag. In a few moments he had the lock open, swung the door wide — and Betty gasped behind him. For behind the door was a blank concrete wall.
“X” tapped the wall, and found that it was solid. There was no egress from the room except by the door by which they had come.
Betty asked, “Must we go back?”
“There’s something queer here,” said the Secret Agent. He stooped and examined the floor with the box-lens. “Here are particles of the graphite leading away from this blank wall. We must have come in through here all right, but this wall is solid, there’s no doubt of that.”
He went back to the other door, into the tunnel, and opened it a crack, then stopped, rigid. From the tunnel, not a hundred feet away, had come the tread of many feet. Then, as he listened, motioning Betty to silence, Binks’ cackling voice came to them.
“If they came along here, they’re trapped all righty. There’s a room down the end of this tunnel, but he won’t know how to get out of it, nohow. The door ain’t got no lock on the inside, an’ you fellows can just rake that room with your machine guns.”
They heard Gilly say, “Boy, gimme a chance at that guy. I’ll cut him in half with lead!”
“X” cautiously closed the door, noting as he did so, the truth of Binks’ statement — there was no way to lock the door from the inside. He snapped his flash on again, saw Betty gazing at him with trustful eyes. She had every confidence that he would get her out of this impossible situation.
Once more he crossed to the door opening on the concrete wall. He closed it, began to throw his light along the wall of the room, on either side of the door. The approaching footsteps sounded louder outside.
Suddenly “X” uttered an exclamation of satisfaction.
Betty asked, “What is it? Have you found a way out?”
“I think so. See this lever? I believe I remember now what this room must be. I was blindfolded when we came in, and couldn’t tell just what was going on. Let’s see what happens.”
He jerked the lever downward. For a moment nothing happened, then there was a smooth whirring of well-oiled machinery, and the whole room began to move upward.
The room was an elevator.
They heard shouts from the tunnel outside, oaths in Binks’ cackling voice. Then the stuttering of a machine-gun. But they were already well above the level of the tunnel, and the shots had no effect.
Betty cried, “We’re going to escape! We’re going to escape!”
“We’re not out yet,” the Secret Agent said grimly. “As I recall it, the entrance to this route was through a cellar. We still have to reach that. And Binks and his crew know we are on our way and can head us off.” He took her hand. “This is going to be a gruelling ordeal, Betty. You must keep a stiff upper lip. I — have doubts now, about our ever getting out of here alive.”