Intense heat funneled down the narrow passageway turning the small space into an impromptu sauna. Twenty foot from the tunnel mouth Clara's face began to prickle with sweat and Emerick's wiped the slick perspiration from her hands onto her combat trousers. With the increased heat came brighter light, and the torches were extinguished leaving a red and orange flickering light to guide their way. Clara's hand trailed along the wall as she walked, the light making it difficult for her to focus clearly but the Doctor stalked ahead impatient and determined.
"Is he always like this?" Emerick asked.
Clara nodded, "Not always. You have hit at least two of his hare-triggers since we met, and he wasn't in the best of moods before we started."
"How do I make it up to him?"
Surprised, Clara stopped and turned to look at Emerick. Sincerity was written in the tight lines around her eyes. Clara placed a reassuring hand on her arm.
"He'll get over it. Just don't try anything heroic. That will only make him worse."
"Are you two going to keep chatting or can we get on with this?" the Doctor's frustrated shout ricocheted off the walls.
The tunnel ended on a narrow ledge of rock that jutted out no more than two feet from the rock wall. A vast cavern stretched in every direction, wide and seemingly endless. No natural light came from above and the inferno below threw giant shadows along the walls making the hundred foot drop to the cavern floor an artist's muse for the depths of hell. As Emerick had described the ledge extended to the left, a natural formation that sloped slowly down towards the flames.
Clara leant towards the edge and inhaled. "Is that sulphur in the air?"
The Doctor nodded. "That's not fire, that's magma."
"We're inside a volcano?"
Emerick shook her head, "No, I don't think so. I've scouted above ground. The main volcano is a long walk north of here."
"If we're lucky, this is a secondary vent and there may be a way out of here from below," the Doctor pushed his sonic shades down his nose and looked at the pit with his naked eyes. "If we're unlucky, this is a dike, a blocked secondary vent which has been cut off by solidified lava."
"Okay, so totally not my subject but how can we survive?"
"I know we shouldn't be able to get that close, but I've been down there," Emerick said, "It's hard to breathe, hotter than the centre of a sun, but it doesn't kill you."
"Fantastic," Clara took another look at the path, "Slow roasting."
The Doctor's face was grim, "Incineration in a matter of seconds if you end up in the magma. That would kill any of us."
They made steady progress in their descent. Despite Emerick's protestations the Doctor took the lead, walking slowly but with no perceivable caution straight down the path turning, on narrow segments, not to face the rock wall but his back to it. Clara had never been afraid of heights but the Doctor's cavalier attitude made her blood run cold and it was all she could do not to shout her angry fear at him.
Emerick had clearly studied the path well on her previous trips. She called out warnings when the Doctor strode further ahead and though he waved her concerns off with a dismissive flexing of the hand, he avoided each obstacle without a hitch in his pace. The path ran at a gradual decline in most places, interspersed with steeper angles and a number of switchbacks. Occasional rock falls slowed their travel. The heat grew more oppressive, Clara opting to keep her sweater over her arms despite the sweat that made it stick to her like a second skin. Emerick paused long enough to shrug off her pack, pulling her shirt over her head exposing a wet vest that clung to her chest. Without the long sleeves Clara could see that Emerick's skin was not the same shade of blue all over, her hands were dark but from her elbows up the pigment was more pale. The gravel tracks in her face continued across the front of her chest and along one shoulder leaving the skin there almost completely white.
With a smile the woman noted Clara's observations.
"Sun tan," she told the human cheerfully, "My kind go darker in the sun. Some of my people lived in the frozen south of the colony, they were almost as white as your teeth all over, except for their hands and faces."
"Some humans get sun tanned too." Clara helped lift the bag back onto Emerick's back, her fingers touching the rough skin at the woman's shoulder by accident.
Emerick winced. "No, it's okay," she said halting Clara's apology. "It's shrapnel. There was an accident before I left home, exploded a cannister of ball-bearings in a drunken stunt with Theos. He took the brunt of the blast, ended up in the hospital wing for a week having them pulled out of his backside. I never confessed to my part in it, so I got to keep the reminder. The ones in the shoulder are the worst, carrying the pack irritates them."
"He must have loved you very much."
Her companion nodded. "It was mutual."
"How did he die?"
Emerick closed her eyes and pushed away the wave of guilt filled grief that threatened to bring tears. "He fell, when we were mapping the waterfall where we found you. I was showing off, climbing higher, faster. I didn't even hear his cry. When I turned he was gone."
Clara reached over and squeezed Emerick's arm.
"I found his pack wash up on the edge of the river a while later. He probably saved my life, even after he was dead. Without his supplies I would have starved."
"Do you think the Women's Institute meeting could wait until we aren't walking along a narrow, degrading path over boiling magma?"
Both women leant over the edge to see the Doctor scowling up up them from the path below, another switchback was just ahead.
"We're coming," Clara replied before Emerick snapped again. "Don't get too far ahead."
"If you spent less time, gossiping you wouldn't be so far behind," he retorted, but Clara could pick out the subtle difference in his face and knew he was, mostly, teasing her.
"Can you wait there?" Clara asked, "I promise we won't say another word until we catch up."
Clara's request was met with rolled eyes, a slight shake of the head, and something that sounded rather like 'hurry up' but the words were lost in a flare from the volcano. Emerick picked up the pace and they found the next switchback a few meters ahead of them. The crumbling edges of the turn disintegrated at their footfall and one or two lumps of rock tumbled away beneath them, landing in a small secondary pool of magma causing a spurt of molten rock to shoot, vertically, about 10 feet.
The Doctor had not waited for them. Clara muttered expletives under her breath but Emerick's face took on an expression of concern.
"What is it?" Clara asked with an uneasy sense of impending doom.
"There's a section just ahead that is becoming unstable. Last time I was here I felt it give," Emerick tightened the straps of her bag making it hug her back like a second skin. "I will try to catch up. Please, Clara. Take your time. When I reach the Doctor he is bound to wait for you."
Without pausing for a reply Emerick set off at a quickened pace. Dancing over the craggy rocks that half consumed the path with a stride not far from a run she was quickly out of Clara's sight. The most dangerous section of the path loomed ahead of her. Here a ceiling to rock jutted out at shoulder height, forcing walkers to stoop and take their eyes from the path ahead. Underfoot loose fragments of rock slid beneath boots and the path narrowed to arms length in places, the foundations of the path giving way without warning.
In a crab-like movement she negotiated the first section, moving sideways, face to the wall, eyes on the path just in front of her at all times. Climbing over a small rock fall Emerick ignored the sweat that was dripping into her eyes and focused on a point ten steps ahead of her where the ceiling rose but path had disappeared entirely.
"Doctor?" Emerick called as she inched closer.
The dirt at the edge of the gap danced as though a snake was moving just below the surface. Emerick blinked and stared harder until she was sure she could see fingers gripping path floor. Dropping onto her stomach Emerick thrust her arm down into the hole and her fingers found grip on the fabric of the Doctor's jacket. The cloud of dust that had billowed into the air with her sudden movement began to settle and Emerick looked down at the grime covered face of the Doctor who was staring back up at her.
"Hang on," she instructed, readjusting her grip so that she held his arm tightly in her hand.
A scowl sat on his forehead which Emerick could not help but think was directed at her.
"Where's Clara?"
"Priorities, Doctor," Emerick reached down with her other hand and took hold of his other elbow with a fierce grip, "You might want to consider getting back up here before worrying about anything else."
"Clara is my first priority," his fingers scrabbled in the dust as he slipped a little away from Emerick's grasp.
"She's fine," she said, "I came ahead because you didn't wait and she was worried. You two are as bad as each other."
Emerick felt herself be tugged towards the edge by the Doctor's weight. If she slipped another few inches she would be pulled straight down after him. The Doctor was clearly aware of the same problem and, as he tried to crane his neck to see how far the fall was, another precious inch of ground was lost.
"How far down is it?" he demanded.
"Forget it," Emerick told him, "There's a pool of magma almost directly beneath you."
"Which way and how far is the drop?"
"To your left. Forty feet." Emerick was gritting her teeth now, her arms were starting to tire already.
The Doctor breathed deeply. Every second wasted increased the chances of fatality. He could feel the tremor developing in Emerick's hands, his own muscles were beginning to ache with the effort of holding on to the fragile path edge.
"Let go."
Emerick's eyes widened, "You have got to be joking."
"On the count of three I am going to let go of this ledge. If you are still holding on to me when that happens we are both going to fall. Our combined weights will force us into the magma. For once in your life, Emerick Hale, do what I am asking."
They slipped again. The Doctor was hanging on by his fingertips now and a third of Emerick's torso was over the edge.
"If this doesn't work tell Clara not to let go of that key until she's in the TARDIS and to use the physic interface to get home."
Emerick grunted her agreement, the pressure on her chest now too much to allow words. The Doctor's lips pulled into a strange grimace of a smile and Emerick realised it was the first sign of real appreciation he had offered her since they met.
And then he let go.