Outside came the steps of the men as they retreated back up the tunnel toward the warehouse exit. All of them, in a group. The little band in the dank cell heard one man say:
“You guys’ll have to jump fast. The water gets this far along in a hurry—”
“O.K.!”
With the cry, the steps outside changed tempo. They became the steps of frantically running men. And at the same moment, down the tunnel in the other direction came a roar of water as the whole Potomac River tried to shoulder into the tunnel running beneath it. The floodgate had been opened!
Nan Stanton screamed once. But none of the others made a sound. It looked like the end, but they only stared at the man they called chief, blindly faithful to him. In a moment even Nan, an outsider, managed to regain some sort of self control, with the example of that icy calm before her.
Smitty thrust his great hands in his capacious pockets, and talked, as a small boy will whistle to keep up his courage.
“The little red man and the dog,” he said. “Nobody’s given an idea as to how they could live in steam. And Mac and I saw them in steam at the Lost Geyser.”
The Avenger shook his head. His eyes were on the bottom of the door. Under the door, water was forcing itself in a solid sheet. It hit the first step up to the cell floor, and then the second. Outside it was a rushing, howling flood.
“They weren’t in the steam,” he said. “What you saw was a stereopticon slide. A man was trying much the same trick from the Senate gallery, a while ago — keeping the Senators in line by making them think they saw visions on their desk tops. That lady’s handbag, Smitty.”
“Huh?” said the giant, moistening dry lips as he saw the flood top the third step and rush over the cell floor.
“A lady’s handbag,” said Benson, “lying in such an unexpected place as Lost Geyser, where you wouldn’t think any woman would be able to go, was sure to be picked up by anyone seeing it. When it was picked up, it set a concealed stereopticon in motion and the mad little man and his green dog appeared against the column of steam. In that way, anyone blundering past Lost Geyser would be apt to be scared away, and wouldn’t be able to talk of what he had seen for fear of being thought a maniac—”
Like the cries of birds, far away, came men’s voices from outside and down the tunnel.
“Hey, what goes on out there?” said Mac, bleak blue eyes beginning to take on a speculative look as they rested on Benson’s white, still face. “What are they sayin’?”
“They are saying,” said The Avenger calmly, “that they can’t get that steel door open to escape.”
“What?” gasped Smitty. Josh and Nellie and Rosabel stared with their mouths open.
“I set the outer bar in such a way that when I banged the door shut from the inside, the bar would fall and block the exit,” said Benson calmly. “I did that because from the nature of the trap and the layout of the blueprints, it was evident that our doom was to be death by drowning.”
“B-blueprints?” said Josh.
“In the Congressional Library.” The water was up to their knees, and spurting in around the dungeon door in flat sheets. “Blueprints of this abandoned traffic tunnel are there, naturally. I stopped on my way to have a look.”
“So you let the men and their precious leader, Fram, throw the lever that will drown them all like the rats they are!”
“I don’t take life, as you know,” was The Avenger’s calm, cold retort. “If murderers kill themselves in their efforts to kill us, that is their own affair. So I let them throw that lever, knowing that by the time they found the steel door locked against them they wouldn’t have time to get back and shut the floodgate again. By then, the rush of the water would have cut them off from it. But they had their chance. You heard me warn Fram not to do it.”
The cold, even voice was like something coming from a machine — a machine of vengeance — rather than a human being.
“But, Muster Benson,” spluttered the Scot. “Ye’ve killed us, too. We’ll be drowned along with the rats. Look at this, now!”
The water was up to their waists.
“What I saw in the blueprints at the Congressional Library,” said Benson, “governed my procedure here. This cell, the only logical place for prisoners in the tunnel length, is in a bend of the tunnel, and its roof is four feet above the roof of the tube outside. It is logical to assume that inrushing water will trap air in this cell.”
“So that’s why you stuffed the crack at the top of the door!” Josh said.
“Yes.” The Avenger’s tone was as even and unmoved as if they were all at a garden party speaking of the arrangements of flowers. “That was to keep the air in this cell from oozing out the top of the door as the water pressed in at the bottom. It’s impossible to caulk the door cracks to keep the water out. The pressure is too great. But it is possible to keep the air in.”
Smitty and Mac were silent. It all sounded very smooth and easy; but they knew that only a great engineer could have read this possibility in a glance at a blueprint.
And even a great engineer, in a case like this, might have miscalculated a very little.
In which case they would all die.
“The men outside?” shuddered Nan Stanton. The shiver was caused by the icy water as well as her fears. The water was now up to the dainty chin of Nellie, who was the shortest of them.
Benson didn’t answer. But they all knew the reply.
The men outside in the tunnel were drowned. Fram included. The tube was flooded from floor to roof, since no more rush of water sounded. And spurting into the cell around the door. It would soon be up to the ceiling in here. Unless Benson’s delicate calculations of elevation and curve was precisely right.
“It still seems fantastically impossible that Dr. Fram was the head of this,” said Nan. “You are sure, Mr. Benson?”
“Even without his presence here at the end, I would have known,” said The Avenger. Nellie was standing on tiptoe to keep her head above water. “The whole plot was one of applied psychology. Only a professional psychologist, trained in the knowledge of manipulation of minds, could have concocted it. Only a master of subtlety like Fram. Certainly it would have been beyond the powers of an ordinary businessman like Tetlow Adams.”
“But why?” burst out Nellie. “Fram wouldn’t want the helium in the park.”
“There was never a question of helium,” said Benson, watching the inrush of water as coldly and impersonally as if his life were not dependent on it. “Mac and Smitty reported seeing a deer and jackrabbit, at Lost Geyser, with incurable sores on their flanks. Don’t you really know what must have made those sores, Mac?”
The Scot, after a few seconds, emitted a kind of squawk at his own thick-headedness in not seeing it before. Particularly since he was one of the world’s finest pharmacists and an equally fine chemist.
“Radium!”
“Of course,” said Benson. The flood was coming into the cell more slowly. But it was still coming in. “Radium. That’s why Fram wanted to get the park — intending to force Adams to bid it in under his own mining corporation titles. There are evidently pitchblende deposits around Lost Geyser so rich, that animals lurking in the vicinity too long develop incurable radium burns. Such deposits are worth uncounted millions to the man who could acquire mineral rights to Bison Park.”
Nellie gasped aloud, then repressed the sound. She was forced to tread water, now. She couldn’t touch the floor any more.
The ceiling slowly neared them till it was only a foot above their heads, and they were all treading water.
The flood was coming in extremely slowly, as the air between water and roof became more and more compressed.
But it still had not entirely stopped!
Nan Stanton began to cry, first silently and then hysterically. All very well to trust The Avenger as blindly as these others seemed to be doing. But, after all, he was only mortal; even he could make a mistake. Besides, assuming there would remain enough air to keep them alive in here for a while — then what? There was at least a quarter of a mile of tunnel between them and the street exit, filled from floor to roof by water. How could they ever get out of that? And the door to this cell, of solid metal, was barred from the outside. How could they get that open?
The bulb in the ceiling was still burning. Rosabel paddled to Nan’s side and put an arm around her to comfort her. At that moment the light blinked out as water, far away, finally caused a short circuit somewhere in the line.
There was about six inches between water and ceiling.
“All of you,” came The Avenger’s calm voice, “go to the walls. They are rough, unfinished cement. You can find irregularities to cling to, so that you won’t tire yourselves treading water constantly.”
They did as commanded and clung with fingertips to irregularities, with their faces tilted so that nostrils and mouths were in the thin stratum of air.
And then the flow had stopped. Benson had calculated the air pocket in the cell, in advance, to the inch.
“Pressure is equalized,” his calm voice came. “We’ll leave now.”
Nan Stanton couldn’t guess what he meant. But his aides knew.
He had his small combination gas mask and oxygen dispenser under the lining of his coat. He clipped that onto his nostrils and over his mouth; then he sank on the floor of the cell, taking in oxygen from a rubber bladder as he did so.
Also with him, as usual, was one of Mac’s inventions. A tiny blowtorch whose fuel was several pellets which, when crushed and moistened, produced a blue, terrifically hot point of flame.
It would work under water as well as in air.
They could all see the blue point move slowly in a circle, under the water, as Benson cut a hole in the steel door. Then a little wavering of the water told of the door being partly opened.
Benson’s head came above surface again.
“Stay in here till I can get to the lever and close the floodgate. Then I will go on to the steel bulkhead door and burn that open. That will allow the flood to go on along the rest of the tunnel till the surface at this end is several feet below the tunnel roof. You can swim out at your leisure. When you feel the water move, follow me.”
As simple and easy as that, to hear the man with the paralyzed face and the pale, deadly eyes express it. But what miracles of applied science and engineering forethought lay behind this incredible escape!
“He’s a great mon,” said Mac, in a hushed tone.
“And a lonely one,” murmured Nellie Gray, profound sympathy in her voice.
She knew better than any of them, perhaps, how desolate was the world in which Benson moved. His was a death in life, without the wife and daughter that crime had taken from him.
Now he had won again. An entire gang, with their cold, subtle, inhuman leader, had been destroyed by their own hands — as gangs of crooks fighting The Avenger always were destroyed; since he himself refused to take life.
A great treasure had been taken from scheming hands. Now, a large source of radium would be opened to relieve public suffering at a cost low enough for the majority to afford. A great public benefaction.
Yes, he had won again. And with their own lives saved. Nellie could picture the awesome personage, whose face could never express an emotion, going calmly under water to the lever, shutting it off, going on to burn through the flood bulkhead and open the doorway there. Then he would be carried in a rush of the released flood till he could get his footing again, and open the final manhole cover for them. And there would be other bodies swirled through the door with him. Dreadful, staring things. Dead gangsters and — Dr. Fram, diabolical in life, harmless in death.
But the victory would mean nothing to The Avenger. Nothing save release of brilliant energies for another case; another brush with criminals too subtle for the police to handle; another chance to avenge the death of his dear ones—
The water began to suck from the cell, waving their legs in its passage. The bulkhead door down the line had been opened, and the floodgate shut to prevent the entrance of more water. The way to life and safety was clear.