As formidable as it appeared, the Sanctum hadn't been designed to repel an army. The trees gave the Doctor cover all the way up to the wall and he leaned with his back to it, his eyes on the swivelling CCTV cameras at the top, uncoiling the tow rope he had purloined from the forester's truck in a clearing in the wood. He knotted it firmly around the tyre iron he had found in the same vehicle and tilted his head back to survey the wicked array of razor wire along the top of the wall.
"I could have been Lord President of Gallifrey, but noooo..."
He swung the tyre iron up over his head on the end of its rope and felt it hook on the top of the wall. He gave it an experimental tug and gathered himself for the climb.
"I could have been head of cosmic analysis at the university by now..."
His words came between gasps as he dragged himself inch by inch up the rope, shoes scrabbling at the concrete, knuckles skinned where they scraped against it.
"But oh, no..." He grunted and scrabbled at the top of the wall. "I had to see the wonders of the universe, didn't I? I had to get out and get involved. Not for me a nice comfortable laboratory with... mmf... service droids attending to my every need."
He gulped in a breath, twining his ankles around the rope, and fished in his pocket for his sonic screwdriver, lifting it and poising it over the bulky mass of one of the electric fence's power packs. It took a matter of seconds before a vibration told him he had found the right frequency and he deactivated it as easily as clicking a switch. He pocketed the screwdriver and gathered himself for the effort of dragging his feet up onto the wall ready for a leap over the razor wire.
"If my metaphysical calculus class could see me now..."
Limping a little from the landing, the Doctor made a swift but ungainly progress across the lawn, past the rosebushes to the Sanctum itself. As he had suspected, he had no difficulty in finding a pair of steel doors set into the base of the structure leading down into the basement. A heavy but simple lock yielded swiftly and he was sliding down the rails of a flight of steep concrete steps into darkness.
Storerooms, ventilation, fuel storage tanks. He slipped quickly past them all, stopping only to pick up a coil of heavy copper wire from an equipment locker. He hefted it thoughtfully in one hand as he pressed on deeper, his eyes on the ceiling pipes, finding his way along more by instinct than by memory till he was certain he was the area he and Angela had penetrated the previous day.
"Come on, then, I know you're around here somewhere."
He found a thick copper pipe earthed into the ground and twisted the wire around it, slowly winding it about his fingers and thumbs while his eyes searched the ceiling.
There was silence. Time passed but the Doctor didn't stir. He stood alone in the dark, the wire forming a gleaming cobweb around his body. An hour slipped away, the engines of the generator thrumming through the murky concrete passages. At last his eyes flicked sideways.
"Ah... there you are."
The silver-white glowing cloud collected at a corner of the floor, as though seeping up from the ground through cracks in the concrete. The Doctor's cold impassive face didn't flinch as it gathered and grew. His fingers tightened on the wire and he drew in a breath.
"Come and get me, then."
It reached for him like a fist, entwining him, encircling his throat, swirling at his nostrils, its light growing into a blueish spark, fizzing and popping against his unmoving body. The Doctor stood like a statue, at first with no sign that anything was amiss, and then the faintest twitch of his upper lip and the corner of his eye. The wire stretched taut between his hands and his knuckles whitened, but still he didn't stir. His eyes stared, and little by little started to gleam with moisture. His immobile face quivered, his cheeks becoming sunken as though the life was drying out of him. At last the cloud's glow started to fade and weaken as though punctured. Moment by moment its mass diminished and its grip on its intended victim slackened. It poured away to nothingness at the copper pipe on the end of the wire.
The Doctor let the breath he had been holding slide out with relief. He dabbed his index finger to the corner of one eye and inspected with an air of puzzlement the single glittering teardrop he found there. He flicked it away and dropped the wire to the floor.
"Water vapour contained by a static electrical charge. Thought so. Weren't expecting me to be earthed, were you?"
His enjoyment of his own self-satisfaction was interrupted by the clang of a metal door. He whirled, eyes wide and alert, to find Hazelbrook standing staring at him from across the room.
The Doctor craned his neck to look over the paunchy aristocrat's shoulder and see if he had any of his initiates backing him up, but there was no one. Hazelbrook didn't even seem angry at finding him there. His attention was focused on the copper pipe into which the electrical cloud had disappeared. His face was openly astonished, almost awestruck, as though some news he had just been told was too incredible and he was having to convince himself that it was really true.
He stared up at the Doctor and after a moment managed to form the words:
"You... killed it."
The Doctor glanced down at the pipe to confirm it.
"Looks that way."
Hazelbrook collected himself, and regained the calculation which habitually lurked behind his expression of bluff good cheer. He eyed the Doctor closely, and asked:
"Could you... kill a larger one?"