At its deepest, it came up to her waist.
She was just about to call it off, to write the cave off as a misstep in judgement, when she heard it: the echoing 'poppop' of a service pistol.
The sound rang through the cave and seemed to galvanize the remaining members of her squad.
Bullock traded a quick glance with her and she nodded in silent agreement.
Within a few minutes, they were through the thickest part of their watery trudge. And, while the tunnel was still unpleasantly humid and much of the rock was actively wet and slick, it was nice not to be wading through it.
Even better, the cave was widening out, allowing for something more than single file.
"Alright." Coughlin said in a hard whisper, surprised at how loud she had to speak to be heard over a constant trickle and splash of water. "Fire teams, form up. Alpha. You've got point."
Automatically, the groups fell into a double-diamond shape that always reminded Coughlin of an hourglass. Bullock took the front with Brick and Mikhailov on either flank and Greer just about at Coughlin's side. Bravo team took up a similar stand behind her.
"We get anything through this rock?" she shot back at Kuroba who was following tightly at her heel.
"Negative. Any telemetry we might get isn't going through the rock. We're blind."
"But not deaf." she said, reminding Bravo leader of the shots they'd just heard.
"Not at all. At least we know there's something down here that wants us dead." Ludwig sarcastically complained.
"Sounds fine to me." Dixon said in an oddly even tone."
Coughlin glanced back at Ludwig in annoyance and was about to say something when the wall next to the Rifleman exploded.
The man didn't even have time to react as the rocky wall gave way to a single, massive clawed hand that punched through his shoulder and side and tore the entire limb clean off. Simultaneously, the private let out a gut-wrenching scream and squeezed the trigger in shock, his pulse rifle firing directly into the mass of his fellow soldiers.
Greer hadn't even turned around when the back of her helmet exploded.
"6 O'Clock!" Coughlin bellowed only moments before fire from six other rifles joined her own and ripped the beast that was only now crawling from the wall into a fine mist.
But it wasn't alone.
Emerging from the waters they had just come through, from the opposing wall, and from below the path they had just walked, several others emerged.
They were all the same in appearance. None of them were like the hulking centaur like they had seen before, but instead a vicious, humanoid creature with long claws, chitinous armor, mottled flesh, and occasionally slender lashing tentacles. Some seemed to wear shreds of cloth and others had hollow white eyes but all were intent to kill.
And all met a firestorm of rifle rounds.
Twice more a wall gave way but each time the now alert squad greeted the emerging monster with a roar of death that ripped it to bloody chunks. Pieces sprayed everywhere in the close quarters and the earlier warning of a "biological contagion" flashed through her mind as she saw Brick step forward with grenade launcher in hand.
The man was painted red and brown with pieces of the beasts.
"FIRE IN THE HOLE!" he bellowed and launched a grenade that would definitely be against several rules of close quarters combat.
The resulting explosion nearly knocked them all on their asses as several of the recently created tunnels collapsed in on itself.
The air swirling in the dark, smoky tunnel, the squad swiveled in every direction as they waited for the next attack.
But none came.
"Form back up and check your weapons, people." Coughlin said, grinding her teeth. "No more accidents."
She felt sick to her stomach. She had just lost two of her own in a matter of seconds. Ludwig, one of the youngest and arguably one of the more annoying, had still served under her for a full year. Greer for three. She would have to contact both of their families now. To talk to Greer's husband...
Coughlin shook her head, telling herself that this was something for another time.
She caught sight of Dixon who hadn't moved yet.
He was staring back down the tunnel.
He didn't respond."
Dixon glanced at her but said nothing. And then back. He simply stared back down the tunnel. Back towards Ludwig. His expression unreadable.
And then he was back in formation.
They moved unassaulted for another five minutes.
During that time, Coughlin noted two minor injuries and three potentially noteworthy encounters. Brick, who was painted red, was not only covered in the creatures' blood but also had a nice slash cut out of his left arm; clean through the battle armor. Gorman was equally covered in gore. Quinn was bleeding from the forehead after having been bashed against the rockface. And Xi had was covered in SOMEONE'S blood but Coughlin wasn't sure if it was from the monsters or the quick patch job on Brick's arm.
No matter what, she knew they'd all be in quarantine for weeks after this.
She was just picturing the barren, empty cells and the doctors in white coats hiding behind glass when the tunnel opened up to a massive antechamber.
And there, hanging on the wall, was Charlie team. Along with a hundred others.