Tegan held one of the eggs near Nyssa's face so that the Doctor could inspect her neck more closely. He was dabbing at the blood with a handkerchief.
"The cuts aren't deep," he said. "It looks as though the mandibles just scraped you."
Nyssa nodded. "Thank goodness for Turlough." She turned her head slightly to look for the Trion. "Turlough?" she said. "Where has he gone?"
Now three pairs of eyes searched the chamber as the Doctor called the young man's name. He hurried to the entrances of both tunnels, calling into each and peering into the darkness.
"Where is he?" Nyssa asked.
The Doctor returned to her and Tegan. "I don't know. He can't have gotten too far; it's only been a few minutes since he was here."
Nyssa was perplexed. "Why would he leave?"
"Maybe he was looking for another way out," Tegan suggested, but the niggling sense of mistrust began to return to her.
"When did he meet up with you?" asked Nyssa.
"Maybe half an hour ago," Tegan replied.
"He was helping me to move the eggs," said Nyssa, "and then he just disappeared. I didn't know what had happened to him."
Tegan scowled faintly. "He told us he was looking for a shortcut back to the egg chamber, but somehow he had gotten lost."
"Could he have gone just now to search for another shortcut?" Nyssa asked.
"A shortcut to what?" Tegan said. "If there's a volcano erupting up there," she gestured toward the ceiling, "he'd be walking right into it. Why would he do that?"
The Doctor had remained quiet during the young women's discussion. Now, however, he spoke. "I think I'd better go after him."
"But how will you know which way to go?" asked Nyssa with concern.
The Doctor glanced at the tunnel leading to the secondary egg chamber. "He wouldn't have gone that way—he was aware of the insects' animosity toward us—so he must have taken the other tunnel."
"But Doctor," Tegan said, "if he's heading for the surface—"
"Then I must stop him before he gets too far," the Doctor finished. "We are safest down here, as far from the lava and gases as possible. The closer he gets to the surface, the more danger he'll face. I need to find him before he encounters any ventilation shafts."
Nyssa placed her arm around Tegan's waist and took a step forward. "All right. Let's go."
The Doctor turned back. "No. You two stay here."
Before Nyssa could protest, he added, "Tegan, you're in no shape for rushing through these tunnels, particularly when they are unstable. This chamber is well fortified; you should be safe here."
"Unless the insects return," Tegan said.
"The smaller ones probably won't," the Doctor said. "They know now that their enemy lives down here. If the others come back, you must continue helping them. Show them that you are more of a help than a threat." He had already begun to step into the tunnel.
"Doctor!" Tegan called. "How long will you be gone?"
"Not long, I hope," he called back. "But you are both to remain here regardless."
"But—" began Tegan.
Nyssa took her arm and led her back toward the wall. "Come on," she said. "We may as well rest until he or the insects return."
They both sank to the ground, wondering when the earth would cease its trembling.
Turlough moved fast through the tunnel, keeping his arm against the wall to feel his way. He realized that there must be at least one tunnel that intersected this one, so he needed to be certain that he kept to the main passageway. He recalled making a relatively sharp turn shortly after the Doctor and Tegan had found him, so if he could keep moving in a straight line he should reach the surface.
After a time, he found that he could see ahead of him. The darkness had yielded to an odd dusk. The air felt different somehow, too. It seemed to press in on him, making his chest feel heavy as he inhaled. He had to slow his pace to keep from panting.
For a moment he wondered if he should turn back. Perhaps he had ended up in the wrong tunnel after all. Yet the increase in light must surely mean that he was nearing the surface. Thinking back, he felt that he had spent about as long in this tunnel as he had when travelling through it initially with Nyssa. So he must be in the right place…
The earth continued to shake, the intensity varying. There seemed, too, to be an ever-present low rumbling that reverberated through the tunnel. Turlough pushed ahead, breathing more heavily and beginning to sweat profusely. The hazy light seemed to dim then brighten; he blinked against it.
Gradually he became aware of another noise. This was not the steady rumble. It was a scraping sound, vaguely familiar but difficult to recall amid the cloudiness of his mind. He realized abruptly that he was having trouble thinking. How long had that been the case? He blinked again, trying to clear his head.
The secondary noise became louder. The rumbling seemed to increase as well. Turlough backed against the wall to remain standing. The light had changed, but he could not tell precisely how. Was it brighter? Yes, he could see more clearly now. Something was moving just a short distance away from him, approaching him from further back in the tunnel. Whatever it was, it seemed to cause the scritching noise. He squinted.
Three insects were scurrying toward him, their wings lifting and lowering, creating the dry rustling he heard. He recalled that this motion accompanied their aggression. He took a few steps, but the base of the tunnel seemed to roll beneath his feet. He fell to his knees.
In an instant, the insects were upon him, surrounding him, their wings flapping, brushing against him roughly. He tried to writhe away from them, then resorted to flinging out his arms in the hopes of knocking them away. But it was no use; they held him down, pressing their bodies over him.
When he felt something sticky touch his cheek he cried out. "No! Stop it! Let me go!"
His words were muffled in an instant as the insects began wrapping his face with their thick, glutinous web.
The Doctor knew from the changing light in the tunnel that he had to seek immediate shelter. If he were close enough to the surface to see the light, he was close enough to be affected by the volcanic gases. Yet he had not found Turlough. The Trion lad might be unaware of the extreme danger from the gases, or perhaps he had already been overcome by them as he neared the surface.
"Turlough!" he called as loudly as he could. His voice echoed against the dirt walls. The Doctor inhaled tentatively, testing the air. There was a distinct odor of sulfur. Sulfur dioxide and hydrogen sulphide were seeping into the tunnel. He stood motionless for several seconds, weighing his options. He could return to the egg chamber, where he would be safe from the effects of the eruption. If he did continue forward, he would have only a few minutes in which to try to find Turlough, and this would take valuable seconds away from his chances of escaping the gases himself.
The Time Lord was startled from thought by two insects hurrying through the tunnel, toward the egg chamber. They loped toward him, pausing for a moment to wriggle their antennae at him before continuing past. The Doctor noticed that one had a scrap of blue hanging from its wing. Their gait was odd, too, almost as though they were staggering. He saw immediately that they were of the smaller species. As the insects scuttled by, the Doctor grasped the bit of material and pulled it away. He studied it for a moment. It was a small, torn piece of fabric, and he was relatively certain that it had come from Turlough's jacket.
The Doctor hastened forward, silently counting the seconds, calculating precisely how much time he might have before he would be overwhelmed by the gases. He had gone perhaps fifty meters when he saw a light-colored form lying on the floor of the tunnel. At first he thought it was a chrysalis, though he wondered how such a thing might have gotten here. He bent quickly to touch the large object, pulling his fingers away when he felt its stickiness. Through the milky webbing, he could just glimpse a patch of coppery red.
Quickly he felt along the exterior surface of the web. The contours were definitely human. "Turlough!" he cried, coughing suddenly.
He looked up. The light had grown brighter, and he could clearly see the end of the tunnel less than twenty meters ahead. There was something else lying a few meters away from Turlough. The Doctor squinted. One of the insects lay unmoving, wings slightly open and legs already stiffening.
The tunnel shook violently, knocking the Doctor off of his feet. He scrabbled upward as several clumps of dirt fell upon his head and shoulders. He looked up. The roof of the tunnel was cracking, splitting from the force of the shaking. He could not remain here. Breathing was becoming more difficult, too. The gases were entering the tunnel.
He ran to the entrance, holding his jacket over his mouth and nose. There in the distance, perhaps fifty meters away, he saw the edge of the TARDIS behind a small rise. His eyes swept the landscape, watching in alarm as lava flowed in a steaming mass toward the rise. He watched for less than five seconds, calculating the rate of movement, then sprinted back into the tunnel.
When he reached Turlough, he pulled the scissors from his pocket and cut a small patch of the web away from the Trion's feet. He pressed the sticky substance over his nose and mouth then grasped Turlough's ankles, dragging him through the tunnel. He drew very few extremely shallow breaths. By the time he reached the entrance, he was exhausted, aching from the hunched position in which he had moved. His eyes darted to the lava flow. He had precious little time.
Securing his hold on Turlough's ankles, he stumbled out of the tunnel, eyes stinging as the lethal gases surrounded him.
Nyssa and Tegan leaned against the wall, their legs outstretched on the soft earthen floor. Nyssa had listened with awed fascination as Tegan recounted the events of the last several hours.
"But how did you fall into the vent?" Nyssa asked, mulling over her friend's tale.
Tegan shook her head. "I'm not really sure. I was standing near it when the earthquake started, and I had trouble keeping my balance. But I think…" she paused, trying to recall something.
"What?"
"I could almost swear that I felt a hand push me."
Nyssa frowned. "Not Turlough?"
"No. He wasn't even near me. I could see him running toward me just before I fell."
Nyssa had pressed a hand to her chest in relief. "I was certain that he tried to help you."
With a shrug, Tegan replied, "I don't know. After I fell I don't remember anything until I woke up back in one of the buildings."
"He tried to get you out of the vent. That's how he burned his hands."
Tegan arched an eyebrow at Nyssa. "Really?"
"Why does that surprise you?"
Tegan's eyes wandered toward the tunnel. "I'm still not sure if we can trust him. Why has he run off?"
"He probably became frightened, or perhaps he was trying to find a safer place for us—"
"Maybe. He must have gotten pretty far; I thought the Doctor would be back by now."
"We should be all right down here until they return."
Tegan rubbed at her knee. It was throbbing mercilessly.
"It looks painful," Nyssa commented, glancing at the injury.
"I can't say it feels good," Tegan replied tiredly.
The wall behind their backs shook more violently, jolting both young women. A deep rumbling seemed to roll from the tunnel entrance.
"That doesn't sound good," said Tegan.
Nyssa stood, hurrying to the tunnel. She placed a hand against the wall then looked carefully around the chamber. "Oh!" she gasped, her eyes focused on the ceiling.
"What?" asked Tegan, following Nyssa's gaze. A fine dust was falling, heralding larger lumps of dirt.
"I think we should move into the secondary egg chamber," Nyssa said, returning to Tegan and reaching for her hand.
"What's happening?"
"Probably nothing, but we should move just in case."
"Just in case of what?"
Nyssa pulled Tegan up then wrapped her arm around the Australian's waist. "This chamber may not be as solid as it seems."
"You mean it could collapse?"
Nyssa nodded. "Possibly."
"So you're suggesting we go into the other chamber, where those insects are? The ones who tried to rip your throat out?"
"I'm not sure that we have any other choice."
Dirt rained down on them. Nyssa hurried to the secondary tunnel, gently pushing Tegan just inside the entrance. She turned back to the large chamber.
"What are you doing?" Tegan asked.
Nyssa lifted an egg. "I'm going to move the rest of the eggs into the tunnel. Perhaps if the insects see that we've helped them they won't feel so threatened by us."
Tegan yelped as several fist-sized clumps of dirt fell just in front of her. "Here," she said, "hand them to me. Hurry!"
The Doctor felt light-headed, and the images before him swam blurrily. One more step… that was all he needed, then just one more… He forced his feet to move. Turlough's ankles threatened to slip from his grasp, but he kept an iron grip, dragging the prone form across the shaking ground. He was hot, terribly hot, and he knew that he would not be able go much further. The gases were affecting him, poisoning him, killing him.
One more step… surely it was the last he would be capable of taking. Then one more, the final one—and something solid pressed against his back. He dropped Turlough's ankles, and, with the last of his exhausted strength turned to rest his hand against the solid, blue door of the TARDIS. He forced his fingers to retrieve the key and insert in into the lock, waves of dizziness crashing over him. He would have to take a breath; he could not hold out any longer.
The door opened, and the Doctor fought off the vertigo, fumbling for Turlough's feet. He could not see clearly—before him were only vague shapes and colors—but there was something that drew his hazy attention nonetheless. Heat radiated from the ground, and there was a deep, red glow near Turlough's head. The Doctor blinked, willing his vision to clear for an instant. The lava flow was nearly at his own feet, and it seemed to pool around Turlough.
With a final tug, he wrenched the Trion inside the TARDIS then stumbled to the console, falling on the lever that closed the door. The light inside the TARDIS was fading; gray splotches pulsated ever larger, devouring the light.
As consciousness slipped away from the Doctor, he lifted a weak hand to his face, feeling the sticky web that covered his nose and mouth. He had exhausted the tiny bit of air remaining in the miniscule space between the webbing and his skin many minutes ago. He was suffocating, gasping for air that was entirely gone.
His fingers twitched, then his hand fell to the floor. The Time Lord's eyes rolled back, the whites nearly indistinguishable against the pallor of his skin. His body rolled slightly as the wave of lava hit the exterior of the TARDIS.
