by Captain Sammitch
Phil Smith figured it was time to check up on everyone who didn't have some sort of power to protect themselves. Leaving Priest and Ameristar where they were, he headed back to the big cavern, where Leslie Kline was waiting at the entrance.
"We might have a problem," she said, still unsure of how exactly to approach him.
"Wonders never cease," Phil replied. "What is it?"
Leslie pointed to a little girl lying on the floor who looked a bit under the weather. "Rosa over there was running around the cave exploring, and her mother sent me to look for her. I found her over there, off in the direction of the lava vents." Leslie pointed behind her to an offshoot cavern about eighty yards away. "She was fainting and experiencing extreme dizziness. I wouldn't have known what it was if the same thing hadn't happened to me. There's something in the air over there, and I'm afraid it'll spread into here. I need you to go find out what it is."
Phil thought a moment. He walked over to a table, around which a crowd of doctors and nurses had gathered. "We might need your help," he said.
A bearded man in scrubs and the ubiquitous white coat turned to him. "What do you need?"
"First of all, I was wondering who you guys were."
The surgeon smirked. "Since that's so important to know right now. Anyway, I'm Jack Pyle, and I'm usually working in oncology at La Perdita International, but yesterday I was helping a specialist at St. Thomas Charity across the island. The storm hit, and we stayed there through most of the night, trying to keep the backup generators running for the people on dialysis and respirators, but when the eye came and the winds let up, we packed up our non-ambulatory patients and all our vital equipment and headed here. So we're here taking care of our critical patients and getting our equipment running, but we don't know how to handle all the other civilians here. We're trying to establish a triage system, but it's way too chaotic, and we can't hope to restore order in a room this size. Your friends are trying to help, but it's pretty slow going."
Phil nodded. "Why don't we move you all to International? It's pretty high up on the mountain, and it's the sturdiest building on the island by plenty. I'm sure they've got work for you, too, and there'll be plenty of room for your criticals."
Pyle shook his head. "There's too much to move, and the storm's back in force. We'd better stay here and try to help some of these evacuees."
"In that case," Phil replied, "I need two oxygen bottles and whatever you have for detecting unsafe levels of waste gases."
Pyle searched through several large kits and produced a pair of emergency respirators and an odd-looking metal box with a small LCD display and a number of small probes protruding from its surface. "Standard O2 bottles, good for ten minutes, depending on heart and respiration rates. This is one of my new toys; the firefighters and HazMat teams use it to detect any life-threatening substances in the air. Readout will tell you what you have and the concentration. Battery's good for about four hours, but I wanna see this stuff back here well before then."
Phil thanked him and took the equipment back to Leslie. He handed her an oxygen bottle. "Put this on."
"What for?" Leslie asked.
"You're coming with me to check this out," Phil replied.
Leslie paled. "What am I supposed to do?"
"Come along and look pretty," Phil answered. "I'm still not sure if I should let you out of my sight after what's gone down so far."
Leslie sighed. "Fine. Let's go."
The Korystnyj:
"Captain! Sonar contact!"
Tsulygin hurried over to the sonar console. "What is it?"
"People in the water, it seems."
"Should we attempt a rescue?"
"I am not sure. It does not seem like they wish to leave the water."
"What do you mean?"
"The two contacts are swimming away from the shore, seemingly in pursuit of one another. It is almost like they are fighting in the water, despite the storm."
Kozlov frowned. "Can we surface under these conditions?"
"What would we do?" Tsulygin asked. "I am most certainly open to suggestions."
"We can run up the radar and optical periscopes," Kozlov replied. "Also, we can deploy the Ku-band antenna and inform GRU of the situation."
"Very well," the captain replied. "If we begin to take damage from the storm, however, we will submerge immediately." He turned to the helmsman. "Periscope depth!" Tsulygin thought a moment. "Tactical: load torpedo tubes one and two. We are not taking any chances."
Phil made his way down the narrow corridor, armed with only a flashlight and his powers. Leslie was several steps behind him, sweeping the corridor with her own light. The device Phil was carrying began beeping more and more insistently until it emitted a steady tone, accompanied by a blinking amber light atop the metal box.
Phil held it up and read the backlit display. He frowned. "Yep. Carbon dioxide. It's nearly off the scale." Leslie tensed. "Relax," Phil said. "It can only poison you if you breathe it, and we're breathing pure oxygen." He pointed to his mask. "This thing is what's keeping you alive. But I wouldn't hang around here too much longer. These things are only good for ten minutes."
"So should we go back now?" Leslie asked.
Phil shook his head. "We're gonna go to the five-minute mark, then turn around and head back. I want to find out what could cause such a buildup of CO2 in here."
"Why is that important?" Leslie argued.
Phil looked at her. "You must not read up on your geology. Carbon dioxide can build up in huge quantities either beneath bodies of water or in caverns like this one. Seismic activity, or even severe weather, can dislodge those 'bubbles' and release them into the air. The pockets of CO2 drift along at ground level, since carbon dioxide is heavier than air, and they can reach a mile or more in diameter. Entire towns full of people have been killed by them. If we have such a situation here, then at the very least everyone in the caves will die. I'm nobody's hero, and I have no intention of becoming so, but I don't plan on letting everyone die just because I didn't want to risk using a little more oxygen."
Leslie crossed her arms. "What exactly are you gonna do?" she asked, her voice muffled by the oxygen mask.
Phil shrugged. "First, I'm gonna find out where all this CO2 is coming from. Then I'm gonna see if we can either block this tunnel or move everyone to a safer place. You can come with me if you want. If you're scared, you know the way back." He turned and headed off down the corridor, somewhat surprised at the knowledge and capability he had pulled out of his head to match the situation.
Leslie threw up her arms and stomped off after him. "Phil Smith! I can't believe we're doing this!"
Phil didn't even turn around. "I can't, either. How did you know my last name, anyway?"
Leslie rolled her eyes. "We'll talk later."
After a while of walking in silence, Leslie noticed Phil was walking a bit slower. "Are you okay?" she asked.
Phil nodded. "The change in air pressure made everything hurt a bit more. I might have some cracked ribs, and pretty much everything is bruised."
Leslie smirked. "Everything? That's a shame."
Phil laughed. "Not that." He looked at her. "Where's your mind, anyway?"
"That's for me to know and for you to find out. You're the telepath here." Leslie looked down the corridor. "This thing is pretty long."
"I'm going to assume you're referring to the cavern, since you probably wouldn't know about... yeah. This tunnel's been going on for a while."
"When are we going to turn around?"
"Hopefully soon. I'm getting stronger and stronger readings as we go. And I'm not getting any indication of..." His voice trailed off. "Wait a minute."
Leslie tensed. "What?"
"You feel that?"
"Feel what?"
Phil held up a hand. "There's a definite air current going through here."
Leslie touched the cavern wall. "It's wet."
Phil felt the wall. "Condensation from an underground water source." He looked ahead. "Check it out." He laughed. "There's a light at the end of the tunnel."
Leslie looked ahead and saw a faint dot of light that grew steadily larger as they approached.
The ground bucked slightly. Phil stumbled a bit. "That's not good."
"What is it?" Leslie asked nervously.
"If there really is a giant carbon dioxide bubble at the end of this tunnel, then it's beginning to be dislodged."
"And that makes the ground shake?"
"We're dealing with thousands of cubic yards of a heavier-than-air gas, compressed into a small, irregularly-shaped space. It's pushing against rock on all sides. Once that bubble lets go, then all hell breaks loose."
"I still don't understand how that bubble got there in the first place."
"It can be caused by any number of things, from large-scale biomass decomposition to chemical reactions between the groundwater and the soil. But in this case, my money's on volcanic activity."
"I thought La Perdita's volcano was extinct."
"The word is dormant. Geologists are starting to rethink volcanic processes, since so many volcanoes labeled extinct have suddenly come alive in several places throughout the world. Currently, the Earth is passing closer to the sun than it has in about two millennia. This movement coincides with the concurrent motion of Mars and Venus, which has put them closer to the Earth than is usually expected as well. That creates a five-body gravitational problem involving the Earth, the sun, the moon, Venus, and Mars. Gravitational shear forces, or sideways motions, are subtly disrupting the rotation of the Earth's mantle, which lacks the mass and therefore the inertia of the planet's core. This is undoubtedly what's causing such unusual seismic activity."
Leslie blinked. "How did you know all that geological stuff?"
Phil shrugged. "Honestly? I don't know; I just... remembered it. I'll probably forget it before too long. This sort of thing happens all the time."
"So there's a possibility that La Perdita's volcano may be coming back to life?"
"Volcanoes almost never die completely, to begin with," Phil answered. "Geological processes happen on too large a scale and too slow a time frame to understand fully or predict accurately. Even dormant volcanoes stir a little every now and then. That might explain our current CO2 problem. Either way, we're almost there."
Phil's watch beeped. "Five minutes."
"Let's go back," Leslie insisted.
Phil shook his head. "We got here going really slowly. We can run back in half the time. We're almost to the source of these emissions." The CO2 indicator was off the scale. "Make sure your mask is on tight -- the air pressure is going up."
Leslie yawned and stretched her jaw as her ears popped to accommodate the rising pressure. She tightened the oxygen mask on her face.
The ground bucked again. Phil stumbled again and almost fell. "You all right?" he asked Leslie.
"I'll be okay," she insisted.
Phil nodded. "Here we are." He switched off his flashlight as they stepped into the dim light.
If the chamber they had entered from the beach was massive, this one made it look claustrophobic. An underground river forty feet wide flowed quietly through a cavern maybe two hundred feet high, at least twice as wide, and possibly half a mile long. Leslie looked around, astonished. The whole chamber was lit with electric lights similar to those they had seen before, only much larger.
"Look at this!" Leslie exclaimed. "This is amazing!" She looked at the lights high up on the cavern walls. "But who could have lit such a huge space? And how are those lights powered?"
Phil looked around. "This cave may have started out as a natural enclosure, but someone at least attempted to turn it into a fortress."
"For military purposes?"
"That'd be my guess."
"So where's all the carbon dioxide coming from?"
"From there." Phil pointed at the underground river, from which large bubbles could be seen rising to the top and breaking, releasing their contents into the air of the chamber. "That water started out in the ocean, and it found its way in through channels like the one we just walked through, carved below the surface of the water by lava flows. It passed near the volcano's magma chamber -- the place where the crust and mantle meet -- and evaporated, mixing with volcanic gases, particularly with sulfur dioxide. The water condensed and flowed downhill until it got here, and the combination of heat and pressure from below forces it out of the ground in the form of hot springs on the side of the mountain. But the river leaves behind all that sulfur and oceanic salt, which goes into the rock that makes up this system of caves, as well as carbon dioxide, which has been building up down here for quite some time."
"I don't get it," Leslie said, still staring at the lights. "Who would build a base of operations down here?"
"Someone who definitely didn't want company," Phil said.
"So what should we do?"
"We should get out of here before..."
The ground shook once again. Phil and Leslie fell to the ground. This time the shaking was quite a bit more violent, and small rocks started to fall from the cavern ceiling. Leslie tucked into a ball, and Phil crouched over her, placing himself between her and the falling rocks. Behind them, a shower of rocks tumbled from an outcropping and hit the ground, sending up a shower of dust, and blocking the corridor they had entered through.