Illya nodded. "There you are. It's—oh—sixteen or seventeen cycles per second, and I'd hate to guess the amplitude." He coughed and gripped the doorframe tighter as he turned back into the room. "Feel up to a sprint?"
Napoleon rose painfully to his feet, his joints complaining incoherently at the demand. "Just point me and say go. The elevator?"
"The elevator. I think I'll know what to look for out in the street, and Del has enough front-line defenses we should be able to handle it. Tell Mr. Waverly what it is, and tell him to stay in his office. It's big enough and well enough damped, he'll be safe enough to coordinate things."
"Check." Napoleon keyed his pocket transceiver and heard a keen shrilling. "Forget it. They're transmitting a jamming frequency now."
"Okay. Let's go."
They charged out the door, aiming bravely for the elevator seventy feet down the hall. Neither of them fell down more than once, but they took two fifteen-second rest stops in open offices. The smaller size of the elevator car lessened the resonant effect, though the main wave was still there.
Halfway up Napoleon had a thought. "Illya," he said, "what if the unit is underground—in a subway branch tunnel, or the dock area?"
Illya considered, breathing hard, and then said, "Three to one they're upstairs. Not worth splitting up to cover. A truck is easier to move in and out, and Thrush's key word is mobility. I just hope it's out here on Fifty-Fourth, and not all the way around the block. I don't think I could make it."
The door slid open and they stepped into Inner Reception Station Three. The clerk was standing, gun in hand, but her head was down and her arm hung limply at her side. She leaned heavily on the desk.
Napoleon grabbed her as they went by, took the gun from her and pushed her carefully into a chair, where she slumped and gasped. The steel door swung wide and they went through the cloth curtain into the back of Del Floria's. The door was closed but the blinds were up, and Del stood behind an armored partition at the back, watching the shop and the street outside through a one-way mirror with a small control panel at his elbow. He looked up, startled, as they entered.
"You tell me," he said. "All I get from downstairs is questions."
"We're checking out Big Bertha," said Napoleon, "and we may have the answer to all our troubles. Tell Mr. Waverly it's a seventeen-cycle infrasonic tuned to the corridors, and get a full-power defense squad up here on the double. If they duck into offices every thirty feet and breathe deeply, most of them can make it. Get it?"
"Got it."
"Good," said Illya, removing a nasty-looking piece of ordnance from a place of concealment and busily engaging in fitting different parts of it into place. "Don't pop out there too suddenly—they may have old fashioned things such as rifles, too."
Del pointed to a cupboard. "Body armor," he said, and turned to the comm channel. "Gimme the boss. Batman and Robin are here, and they say they know where it's at..."
"I wish he'd save the code for the public," Illya muttered, slipping a bulky jacket and hood over his suit. A nylon fabric of complex weave, it was capable of stopping .30 machine gun slugs at ten yards.
They paused at the doorway and edged it open. There was a snap near the top of the door and a few splinters fell. "So they do," said Solo. "Let's see how high their angle of fire is."
Crouching, he grabbed a coat on a hangar and stuck out one shoulder about level with the knob. The door shook and the sound of two bullets impacting made his head ache more. He heard Del behind him saying something about a customer's coat, then Illya was pulling him to his knees. Painfully he forced his vision back into focus.
"They can't hit the steps or the bottom two feet of the door. Let's go." The two of them dragged the gun like a piece of pipe across the floor and slid it out onto the concrete stoop before crawling after it.
Illya crept up the six steps towards the sidewalk. "What would they do with innocent by-standers?" he wondered aloud as he peered cautiously down the street.
"They probably wandered off about the time the infrasonic started," Napoleon said, crouching beside the anti-tank rifle and fitting a massive magazine into place. "I know I would if I had a choice."
"There we go," the Russian said, changing the subject. "Just up the street. About under where Mr. Waverly's windows would be if they were real windows. And I'm afraid we'll need the armor-piercing. That always hurts my ears."
"Okay," said Solo. "This time you get to cover your ears while I pull the string. I'm checked out on Bouncing Betty here. What do they look like?"
"It's the big blue van on the north side of the street with TIDY DIDY on the back in faded pink."
"You're kidding."
"No; there are two rifles sticking out of the rear end, and I saw a muzzle flash from one about the time we lost a corner of the railing."
Napoleon Solo shook his head. "They have absolutely no sense of decency," he said. "Gimme a hand with this."
A slug plucked at Illya's hood once when he moved incautiously, but in thirty seconds the gun was set up, shielded by the heavy concrete of the steps leading up to the first floor. Illya covered his ears and squinted as Napoleon popped his head up once quickly to check his aim, and then let off a ranging round. A fan of fire washed lightly over the brick wall next to the door and concussion pummelled his chest. A section of pavement eight feet short of the truck burst into a shower of gravel and smoke, and Illya said, "Elevation five degrees and right just a notch."
"Not bad for an instinctive point-and-shoot gunner," said Napoleon, cranking in the corrections. "Cover your ears."
Illya did, and squinted through a crack that had appeared in the cement. The truck rocked visibly as he felt the heat from the backlash, and a black furrow ploughed along the near side of the body, tearing into the cab, which faced away from them.
"Left just a hair," said Illya coolly as a white scar appeared on the sidewalk six inches from his nose and white powder spurted into the air.
"Roger Wilcox," said Napoleon. "Hold your ears."
The gun thundered and leaped on its mount, and Napoleon peered through the shaken air, heedless of cover. Before his flash-dazzled eyes recovered, he heard Illya's voice faintly yelling, "Hit 'em again! Hit 'em again!"
Taking him at his word, Napoleon steadied the steaming weapon and fired two more rounds, two seconds apart, before a flare of ghastly yellow light filled the entire street. His stunned ears were totally numb, but as his vision cleared of dancing green flecks he saw Illya waving his arm horizontally, palm open and down. He leaned back against the side of the stairwell and waited for his head to return to its normal size.
He opened his eyes to see twelve men in dark suits pouring out of the entrance to the tailor shop and hurrying past Illya, who pointed them off down the street. He sat up. His ears weren't quite ready to resume operations yet, but his chest felt better.
He got to his feet and walked carefully over to Illya, who was also showing signs of recovery. Napoleon looked down the street to where the shell of a blue van was charring in the swiftly-dying flame of the explosion. He stared at it, stunned anew, until he gradually became aware of someone saying something behind him. He turned and said, "What?"