The WAV crunched through another thin wall dividing two adjacent tunnels, hardly slowing. Pa-5 had done it the first time reluctantly under the guidance of the HUD, but each time after had been of her own volition. The worry in the back of her mind for a cave-in had reared its head too many times; she'd shushed it, proof of the opposite clearer with each new path she trailblazed.
If she still couldn't generate enough distance, a cave-in might become a necessity. Even the mass of rocks heavy enough to crush her WAV like a tin could only slow the Aud's progress. It would dig through blockage like an excavator, devastatingly efficient in its determination.
The HUD worked overtime, finding new routes on the fly. It was the only thing giving her direction, and by extension, keeping her alive. She fired a different projectile canister over her shoulder after another switch failed to disrupt the status quo. Cave-in it is.
The bulbous orb shot down the tunnel, smacking into the Aud with enough velocity to rock its head. The kinetic jolt upset the contents, causing the orb to contract smaller than a pebble while turning white-hot and melting into the Aud's fur.
It snorted, ignoring the heat. But it couldn't ignore the following combustion reaction. In an instant, the tunnel behind her was consumed in an explosive blaze strong enough to send her flying. The inevitable cave-in came like a second rain, chunks of the ceiling not ten meters above the two crashing like an avalanche. In the first second on the edge of the conflagration, her rear visual feed cut itself to spare her eyes. Even then, being so close still resulted in a ringing in her ears, one stronger than the flash grenade's effects.
She lost track of the Aud, but it still called out. Not in pain. A lifetime of absorbing everything humanity knew about the Aud--which still wasn't much--let her catch the notes of rage powering the outcry. She'd be mad too if her prey was right before her eyes and vanished. But was that cheating? Not a chance.
By the time she stopped tumbling, she was a good twenty meters from her initial position. The tunnel ended five meters from her, the new rock wall quivering from the sudden repositioning. Unsure if it would start spilling out, she forced the suit's servos to pick her up and create some distance. She could still hear the Aud screaming, a muffled wailing that made her cringe. She started again, ordering the HUD to go through each subsystem and perform an emergency survey.
The servos and musculature were fizzing. The battery had received a shock from blunt trauma. Despite working around WAVs all her career, she couldn't tell what that meant for the longevity of the suit. The functionality of the battery core was a black box. Only a select few elite engineers were ever clued into their workings.
Some power lines were severed, shutting down the weapon systems in her right arm. It held her supply of flash grenades, something she disdained. At least the sonic emitters were on the suit's left. She had worried the explosion would set off the other explosives stored in her left; while the launcher was rattled, its payload remained silent.
Surviving twice the original payload at point-blank was out of the question. She received one too many shocks in too little time. She had to slow down, realizing she was gasping. Adrenaline was the culprit, no doubt.
The HUD was a friend, already injecting chemical cocktails to induce calm and negate some aftereffects. Because light WAVs were expected to last in isolated or hostile territory for extended periods, they were the only class that came equipped with internal mixing, injection, and storage faculties for synthesized hormones. She came to appreciate the added complexity of the suit in time.
Stress came easily, even with the added contents to her bloodstream. She clenched and unclenched her hands to occupy them, again identifying that abnormal feeling of boredom. It felt even more inappropriate this time around.
With the site of the cave-in out of sight, the only activity was to check on the drones while keeping an eye out. The one stationed by the entrance had fallen outside her communication radius, although not before sending several detection signals, and later its destruction. She hadn't noticed in her mad scramble to escape. The new hunters should take a while to find her. Even if the additional Aud were more familiar with the tunnels, she at least had the HUD. But that advantage would be null if she didn't get to cracking down and making enough distance between her and the screaming Aud at her back drawing others like a beacon.
At the next fork, she chose to make another new route, feeling the skewed battleground between the integrity of the wall and the force of her suit. It caved even faster to the point where she stumbled from the excess starting distance she'd judged necessary. On the other side was a skeleton. Knocked over from her entry, it splayed across the tunnel floor in a macabre fashion.
The cavern ecosystems and time had weathered away any identifiable features, like technology or clothes. The skull jaw slackened, popping free and clattering away. She took a moment to look it over, finding nothing noteworthy. While it was odd this was only the first corpse she'd found, the others had probably been crushed under hoof by passing Aud over the generations. There was no reason to linger.
The HUD beeped. "Notice: Tertiary checkpoint has entered into sensory range. Estimate: At current distance traveled, will arrive in twenty minutes."
Good. Even after all the panicked maneuvering, the HUD stoically refused to make an error in its constant vigilance. One of the drone feeds went blank. Frowning, she brought up the adjacent drone's feed, ordering it to investigate discreetly. It dashed like a jackal along the walls, well-oiled servos providing no friction. The resonant hums of the tunnels were the only companions on both ends.
While the first investigated, she sent the second round on a U-turn to check on the progress of the yellow. It had an easier time reaching its destination, only needing to locate the trail of destruction before following it to its conclusion point. Two more yellows had joined the first, growling at it while it fruitlessly dug. After no changes occurred at the scene, she pulled the drone back, setting it back on its original directive to scout the upcoming greater tunnel.
It'd been long enough in the Lesser Tunnel System. Even with the advantage her WAV's smaller size brought, if another beast tailed her again, she had no guarantees the HUD would be able to puzzle out a continuous escape path like before. She was a mouse in a maze, hunted by cats that could squeeze through nearly any space. She would only be able to persist until she was cornered by tunnel walls she couldn't break through.
Two segments of the Greater Tunnel System were positioned far to the west, and below her current position, based on the map the HUD updated. She noted with slight satisfaction that it also segmented the tunnel she'd caused the cave-in at, representing a break in the natural subterranean architecture.
She decided to head for the one dozens of meters below her. She wanted to eventually come back out into the Gaiss Hollow, not begin a one-woman exploratory survey. After informing the HUD of her choice, she sat back and let it puzzle out the next series of routes while continuing onward at a moderate pace. After the previous encounter, she was wary of leaving her back unchecked for too long. This newfound paranoia spared her twice when she hid from an approaching growl or noise. Her breath caught in her chest harder the second time when she realized she was mere meters from an unaware blue fur. She nearly cried when it looked like it would settle down right in the center of the tunnel for a nap, but a far-off clatter aroused its interest.
She waited until the predator was out of sight, then waited longer still. And even longer after that. Only after her knees began to cramp inside the WAV from its crouching position did she hazard a glance outside her little hidey-hole. The coast was clear. This time, she shed a tear from relief.
She wasn't far from reuniting with the Western Greater Tunnel System by this point. Enough time had passed in silence that she risked unlatching the launcher on her right arm and emptying it of its contents. She discarded it under a pile of boulders pushed up against one of the walls. She wouldn't take any chances of an inquisitive Aud discovering it and then hunting her like a bloodhound. They'd already be after her scent if the suit wasn't airtight, filtering both the air expelled and taken in to remove any harmful or incriminating elements.
The remaining flash grenades were pocketed in one of the leg compartments; she kept one at the ready in her palm, fingering the cylinder. Without the launcher, she couldn't prime it, so she'd just have to throw it hard enough to breach the casing when it landed in the vicinity of its target.
The HUD informed her that it had been over twelve hours since she'd consumed any matter or fluids. Only then did her resentful stomach flare up, grumbling within the suit. Her throat followed suit, finding the strength to become parched at what seemed a moment's notice. She grunted, silently cursing her traitorous body. Yes, she was hungry and thirsty; soon she'd be tired too as she would begin cutting into her body's allotted sleeping time, but the only option was to continue forward. The lack of food within reach also made the situation more bearable, as did the convenient lack of a bunk. The suit took care of her immediate needs, injecting two more cocktails.
The first quieted the urges rising in her stomach, the signals between her brain and digestive system hijacked. It would now believe the body had received its sustenance. The second was like a strong shot of caffeine, jolting whatever drowsiness she'd been accumulating right out of her. Along with the aftereffects that came from high doses of liquid sun, the total withdrawals wouldn't make her recovery anything pretty. Again, if she made it back.
She could at least deal with her thirst. Being cave systems, both the Greater and Lesser Tunnel Systems were incredibly damp, which while making them a perfect breeding ground for all kinds of icky critters, they were also chock full of water. It just wasn't immediately available. Her WAV's collection and purification faculties had been working of their own volition ever since she reached the quaternary checkpoint. A nozzle inserted itself into a corner by her lips, prodding lightly to be let inside.
The cool, refreshing rush woke her up even more than the caffeine cocktail had. She sucked greedily, taking the chance to empty her suit's accumulated reserve and fill her stomach, even if it was just on fluids. The clarity it brought was a nice bonus too, the normalcy of such an action even managing to calm her nerves a little where the hormones had failed.
The drone scouting the greater tunnel below her provided some grim news: at least one Aud was present every two hundred meters within the twisting track of continuous caverns. Most of them were of a low level, but all they needed was a single alerting cry to come swarming. She shivered, the wall of death her drone had recorded at the failing fort still fresh in memory. She wondered if the engineers in the underground garage had had a chance to fight back, to get into suits of their own before they were torn to shreds.
The one thing she wondered at was the sitesman. Where had he been located? Even during the fitting process for the suicide messengers, he'd observed via transmission. His office was located at the center of Fort Io, but the sector it was in was one of the first to be overrun by the dropping Aud. Even from a distance while heading toward the quaternary checkpoint, she'd been unable to catch sight of the normally towering building, and could only assume that it had been knocked over by one too many impacts from above.
So had the sitesman survived then? Was he in an underground bunker? Or were all of these thoughts just wishful thinking she entertained, wishing she could verify that at this point, she and whoever was left of the messengers weren't the only survivors?