Simmons couldn't hear a thing through the bulkhead doors.
Everything had fallen silent, and it made her uneasy. She would even have preferred to have heard the Arachnids scratching away at the doors. At least she would know what they were doing.
She chewed anxiously on her thumbnail. All she could do was wait.
She couldn't shake the Doctor's words from her mind. She wanted to help, but knew that he would never let her.
There was a noise. A thump, from the far bulkhead door.
To her dismay, the door began to open.
The Arachnids had broken through.
The first of the spiders swarmed through, as soon as the gap was wide enough for their bulbous bodies.
She began to panic. She was trapped in here.
Simmons backed up against the door, as flat as she could physically make herself, as the Arachnids crawled all around her, hissing.
"Doctor…" she whimpered, quietly. He wouldn't be able to hear her.
The Arachnids stopped, as though frozen in time.
Simmons held her breath, but the spiders refused to advance further.
Then as quickly as they came, they scuttled away.
Simmons heaved a sigh of relief. It was over. The Doctor had defeated the Arachnid Queen.
There was a jolt, and the door behind her began to slide up.
She prepared to meet the Doctor's smug expression, as he triumphantly explained what he'd done, whilst constantly reminding her just how much of a genius he was.
Her face fell.
Instead, the Doctor was hunched on the floor, desperately clinging onto Charlie's arm.
Charlie looked up, more scared than he had been, trapped in a web.
"Help me!" he begged.
Simmons rushed over.
"Doctor!"
The Doctor was gasping for air. His blue jacket was in shreds, and his arm was bleeding.
"What happened?"
"The Queen bit him. He's been poisoned," Charlie's voice wavered.
Simmons glanced over at the twisted husk of the Arachnid Queen, lying dead against the wall.
The Doctor's arm looked bad. It was badly infected, pulsing with gangrenous globules.
"We'll get him to the med-bay. Manufacture an antidote."
Simmons helped Charlie support him, pulling his arms over their shoulders.
The Doctor shook his head. His face was pale, clammy; almost glowing under the effect of the Arachnid's venom.
"It's too late for that," he muttered.
"Don't say that," Charlie croaked.
Simmons could tell he was terrified – completely out of his depths with the Doctor hurt.
"No," the Doctor wheezed. "We won't make it there in time."
They began to make their way out through the decontamination chamber.
"Charlie, there's something important that you need to know."
The Doctor was struggling so much to speak, that Charlie had to try and convince him to keep quiet.
The Doctor ignored him.
"When I die, there's something that happens."
"You're not going to die," Charlie implored.
"When I die, there's this process… called regeneration."
"Oh, no…" muttered Simmons.
The Doctor groaned, as if he was about to throw up.
Charlie looked desperately at Simmons. She seemed to know something he didn't.
"Regeneration?" he exclaimed. "What are you talking about?"
"When my body… is critically injured…"
The Doctor jolted sharply, his face contorting, and yelled in pain.
"It… fixes itself," he managed to grunt, through gritted teeth.
"Every cell in his body regenerates," Simmons quickly explained. "His DNA is rewritten, and… he changes."
"I don't…" Charlie spluttered. He didn't understand what they were trying to tell him. "I'll just… I'll just get you back to the TARDIS."
"Yes!" the Doctor roared. "The TARDIS!"
They continued down the corridors of the Moonbase, heading for the TARDIS.
The Doctor made an effort to walk, but he couldn't keep up with Charlie and Simmons' hurried pace. His boots kept slipping against the metal floor, and they practically had to drag him along.
They sometimes saw an Arachnid, perched in the corners of the ceilings, completely at a loss for what to do.
Charlie knew that they wouldn't survive. He couldn't remember if the Doctor had explained, or if he knew because he had been connected to the Arachnids, but the spiders couldn't survive without their Queen. The males would all shrivel and die within the year – if they weren't exterminated by the UNIT soldiers first. They couldn't reproduce without a female: the Queen.
Their journey was a blur. Charlie was concentrating only on getting the Doctor back to the TARDIS.
There were other people around them, as they staggered down the corridors. Other UNIT personnel, watching the Doctor pass with concern. Charlie spotted Professor Lakowsky, and Lieutenant Shah, both gaping at him.
Another woman - whom he didn't recognise – kept offering to help, but there was nothing she could do.
Charlie began to recognise the area where the TARDIS had landed. The familiar blue box came into view, and he had never been so pleased to see it.
Surely, there'd be something on board the TARDIS that could help the Doctor. He'd know what to do. They just needed to get him inside.
Charlie fumbled in the Doctor's pocket for the TARDIS key, and thrust it into the lock.
Suddenly, he was alone in the TARDIS with the Doctor. The Doctor had collapsed to the floor, his knuckles scratching at the grating, as he struggled for breath.
He rolled over onto his back, wincing in agony.
Charlie glanced back at the police box door. It was shut, and there seemed to be no turning back. He crashed to his knees beside the Doctor.
He tried to take his pulse, grasping the Doctor's trembling wrist. For the first time, Charlie realised how frail the old man was.
"Don't… look so worried," the Doctor grunted. "Left heart's stopped beating. In a minute, the right's gonna go, too."
"What… what do I do?" Charlie urged, shaking his head.
"It doesn't matter, though," the Doctor continued, managing a chuckle.
The Doctor wrestled his hand into the air, and slowly twisted it around, closely studying his palm with unfocussed eyes.
Charlie wound his hands together anxiously. There was a disconcertingly distant smile stretched across the Doctor's face.
"You're going to… regenerate?" Charlie questioned. "Are you… are you sure?"
The Doctor eyebrows coiled into a frown, and the smile faded.
"Oh, no," he whispered sharply.
"Doctor?" Charlie repeated. The Doctor, however, didn't seem to hear him.
"Something's gone wrong," he whimpered. The Doctor's voice was cracked, his breathing shallow. He sounded scared, all of a sudden. He'd kept very calm until a second ago.
Charlie felt helpless. The Doctor gasped sharply, and threw his head back, teeth clenched, flecks of spittle escaping as he thundered; tortured.
"What do I do?" Charlie mouthed, unable to utter a sound as the Doctor writhed beside him.
Without warning, the Doctor stopped moving, and lay still. Charlie held his breath, unsure what to do next.
The Doctor fixed his watery gaze upon him, and blinked. He was frowning, as if he didn't quite recognise the person kneeling at his side. A tear welled out of his eye, and snaked across his temple.
The Doctor's last breath was drawn out; all the air in his lungs fleeing his body.
Charlie was paralysed. The Doctor's shape was rigid, his hand slung limply by his side, a bruise still blossoming across his skin.
The Doctor couldn't be… dead? He can't be.
The TARDIS seemed to know, and had fallen into melancholy silence. Or perhaps Charlie was so upset, he could no longer hear the rhythmic pulsing of the engines.
"Charlie?" a voice spoke softly into his ear.
Charlie reeled back in shock, and threw his hand out beneath him to keep his balance.
There was a flickering holographic figure crouching next to him. It was a figure of a man – rather, a boy, about his own age. He was staring down at the Doctor, a familiar brooding expression dominating his face. The last face Charlie had expected to see.
The boy turned to face him, his features strangely blurred as the holographic pixels moved. His eyes sparkled as he looked directly at him. Despite the figure before him being a monochrome image, those eyes were so full of life.
"We can still save him, Charlie," the figure assured him.
"Nate?" Charlie breathed in disbelief.
His slightly swollen lips curled, and the holographic figure smiled a brilliant, boyish grin.
To Be Continued…
The Twelfth Doctor and Charlie will return in: Shadows of My Mind.