As she remembered, the passage soon came out into the subway tunnel itself along with a green tiled platform. It had been modified by the BTC long ago to accommodate vehicles—which was no longer necessary; a ramp ran down to where the tracks would have been laid. Everything was covered in dust. The arched masonry work was impressive, but that’s the way they used to build things, she thought.

From here the tunnel was a ruler-straight shot to downtown, about two miles away. The soldiers were already ahead of her, obviously eager to get back to base and get their reward for a job well done. They grabbed their prisoner’s container and shifted gravity to drop into the twenty-foot-tall shaft as though it were a massive well, and with a whoosh they disappeared into the tunnel.

Alexa powered the gravis first across the platform and then, running along the tiled wall, fell after them in the darkness.

Precisely what she was going to do next was a big question. They were heavily armed and armored. She was not.

She glanced at her display and confirmed that they were at terminal velocity—one gravity. That meant at a descent rate of about one hundred seventy-five feet per second, she had roughly sixty seconds to figure out what to do. After that, they would have arrived at the edge of the BTC complex, and she’d have nowhere to hide.

She clapped her arms to her sides and gained on them as they fell in a leisurely free-fall posture. Four of them were arrayed as a stack, one falling below the other; two additional men up front fell side by side, the transport shell below them. As she came up on the rearmost operator, she could see the soldiers were equipped with standard assault armaments: glove-based gravity projectors and XD guns, infrared lasers, psychotronic weapons. Basically enough firepower to vaporize her several times over—especially since she was only wearing a tac suit. These guys were clad in armor where the impact of a twenty-millimeter cannon round could probably be buffed out with beeswax.

But then, there was always their kinetic energy to make use of . . .

Alexa came up behind the rearmost soldier as a worker’s alcove loomed into view in the tunnel wall ahead. She moved beside him and elbowed him toward the wall.

Before he could adjust or even react he impacted face-first into the stone abutment at a hundred and twenty miles per hour, the diamondoid helmet smacked against it like a billiard ball. Alexa adjusted her gravity just in time—the stone wall rushing past just inches from her face.

Looking below she could see that none of the others had heard a thing over the roar of their descent down the tunnel. A glance back showed the smashed operator’s body still hurtling down the tunnel behind her, still in its own gravity field, as if the subway tunnel were a mine shaft—but the body was bouncing off the walls the entire way.

That was going to be a problem sooner or later . . .

Alexa slapped her arms onto her thighs again and accelerated toward the next soldier. This time she reared back and kicked him into a buttress of stone, and weaved back into the center of the tunnel as his armored body sheared some of the stones away from the wall behind her. As the stones got caught up in his gravity field, they started clattering down the tunnel behind her along with his body.

That was going to be another problem soon, too.

She descended headfirst now and spun the legs of the third soldier, causing him to cartwheel into another service alcove. He stuck there for a moment before the other bodies struck him and dragged him down the tunnel.

Alexa estimated she had barely fifteen seconds left before they reached the end of the line, so she streamlined herself as best she could and spun the fourth soldier into the wall, shearing off a metal pipe in the process.

Seeing lights ahead, she pulled back slowly on her gravity field—looking behind her to bat aside bodies, rocks, and other debris that fell slightly faster than she did. As they passed her, her gravity field was warped, and she pushed off the wall at one point, narrowly avoiding another buttress.

But moments later she was behind all of the falling debris, and she cranked back her gravity in full reverse. Within seconds she had slowed to a stop—at which point she killed all gravity reflection and tumbled to a stop, standing on the floor of the tunnel. She was glad that railroad tracks had never been laid.

She then glanced up ahead to see that the two lead operators had come to a stop, placing the transport shell on the ground between them at the entrance to the BTC tunnel complex. Just as they turned around, the dead bodies of four of their comrades and assorted masonry hit them at terminal velocity and smashed them against the back wall—where they all stuck like bugs on fly paper in the altered gravity fields of the dead. For all intents and purposes, the fallen had just hit the bottom of a two-mile-deep mine shaft.

Alexa pulled her positron pistol and closed the final hundred meters on foot. As she came out into the lights at the entrance to BTC tunnel sixteen, she could tell the security detail was out of action. The impact alone probably broke their skulls within their suits—or at the very least knocked them unconscious.

She holstered her pistol and raced to the matte-black, aerodynamic transport shell. It was lying upside down, so she rolled it over and opened the control panel. She pounded the “open” button, and it hissed as the lid rose.

Jon Grady was strapped inside, asleep, and she started slapping him awake.

“Jon, get up! Wake up!”

Grady came around, greatly confused as he covered his face. “What? What is it?”

She grabbed him by the shirt collar—since his gravis had apparently been taken. “It’s me, Alexa. We need to get moving.”

He nodded, still looking confused, and slowly climbed out of the transport shell. He glanced around. “Where are we?”

“The edge of BTC headquarters. There’s a security gate ahead, but the chief AI construct has agreed to help us.”

“Hold it, what? Let me get my bearings.” He stopped as he saw the six armor-clad operators lying in an unnatural gravity field against the wall—blood now pooling around several of them at an impossible angle. “What the hell . . . ?”

“It’s a long story, and I don’t have time to tell it. Hey, wake up!” She slapped him.

“Ow! Okay, I’m awake.”

She opened the cargo hold of the transport shell and found his makeshift gravis and helmet. “Put these on while we’re moving. AIs will have noticed these guys flatlined, and we need to be long gone by the time reinforcements arrive.”

Grady nodded. “Okay. How much of the plan worked so far?”

“Enough. We need to get to the Gravitics Research Lab.”

“And security?”

“Either it’s not a problem, or it’s impossible. And we won’t be able to find out by standing around here.” With that she activated her gravis and started gliding down the well-lit corridor toward a sealed vault door. There was a large number sixteen etched into it, and a control panel to either side.

As she stopped, Grady came up alongside here, powering down his own gravis.

Alexa looked up at the vault door. “Varuna! Let us in.”

“There are already security elements headed this way, Alexa. I cannot restore your access privileges, but I can switch your biometric profile with that of the nearby deceased team leader . . .”

The vault door boomed somewhere deep in the rock and then started rolling aside.

“This will be discovered soon enough, but it should buy you some time.”

“Thank you, Varuna.”

Alexa ran into a white corridor surrounded by equipment rooms with armor and uniforms in racks. Nearby was what appeared to be a security post. It was vacant. Klaxons were sounding and lights flashing. “Where is everyone?”