“Is everything set?” Professor Bennett asked.
A technician checked a bank of computers, looked down at a clipboard and gave a cautious pause. He couldn’t help but glance over at the dais in the centre of the laboratory nervously. Bennett coughed to draw his attention, and then instructed him rather tetchily to carry out the pre-experiment checks again. Five years he had worked getting this experiment ready, and still he had to convince people he was really going to go through with it.
“Start recording the control readings now,” he called to his assistant, Weakes. “Without the data, the experiment is worthless.”
“Ha!” came a derisive snort from the corner of the room.
Bennett closed his eyes for a moment, and ignored it.
“I don’t know why you’re being so unhelpful about all this,” a strident female voice scalded. Bennett tried to carry on his final checks. “The Professor is trying to prove the existence of parallel universes. I would have thought that was something you’d appreciate.”
“On the contrary, Miss Smith,” the imperious voice objected, loudly. “This is exactly the sort of dangerous charlatanism I’ve denounced from one side of the universe to the other. This isn’t science: it’s suicide.”
“You made your objections quite clear at the proposal stage,” Bennett snapped.
“And I shall make them again, sir!” the Doctor bristled.
Bennett looked at him. And old man with a hooked nose and an Inverness cloak. Why the UN’s funding body placed so much credence on his word Bennett couldn’t begin to imagine. But he didn’t have to listen to him any more.
“Your UNIT pass may mean I can’t ask you to leave, Doctor,” Bennett said coldly, “but it doesn’t mean I can’t have you gagged. Please stop disturbing my preparations.”
“You preparations are very disturbed indeed,” the Doctor wouldn’t be stopped now. “The quantum machine gun is a purely theoretical experiment. The idea that anyone would think to attempt it in reality … Why would you, man?”
“I’m not endangering anyone else,” Bennett objected. “As you well know, I intend to be the only subject.”
“Wait - endangering?” the Doctor’s assistant, a small dark-haired young woman who Bennett seemed to recall was also a journalist, chipped in. “I thought that thing was rigged to jam?”
She pointed at the dais in the centre of the room. Everybody looked, nobody could help themselves. The machine-gun stood there on its tripod, glowering at them. It looked icy cold to the touch, heavy with menace and portent. Wires ran from it to a small computer independent of the measuring instruments. In a few moments, Bennett would find himself staring down the barrel of the gun.
“The apparatus is designed to fire or jam based on a quantum event,” Bennett explained, as he had a thousand times before. “Imagine a coin toss: heads it fires, tails it jams.”
“So it could still fire!”
“Of course! That’s the whole point of the experiment,” Bennett’s voice was calm, which only seemed to horrify the Doctor’s assistant more. “When I stand in front of the apparatus - if there are alternate universes - then it will jam again and again and again, and my machines will record any fluctuations in the ambient readings. I won’t come to any harm.”
“Well, that’s alright then, isn’t it Doctor?” the girl asked, cautiously. “I mean, we know there are alternate universes, don’t we?”
“That’s not the point, Sarah-Jane,” the Doctor said, eyeing Bennett. “The quantum machine-gun only works from the subject’s point of view, do you see? No, you don’t see. Listen - with each quantum event, there are two alternate universes: the one where it happened, and the one where it didn’t. The coin lands on heads and tails. But you can only see how the coin lands in a universe where you’re alive: that’s how the experiment works. With each quantum event, the machine-gun jams and fires, but because the subject dies whenever the machine-gun fires, they can only observe the result in the universe where the weapon jammed.”
“So they stand in front of the gun, and it seems to jam every time,” the assistant said, understanding. “No, wait a minute -“
“Exactly,” the Doctor said. “Only the subject travels between the alternate universes. We will still be here in this universe, watching Professor Bennett getting gunned down by that infernal machine.”
“It’s inevitable,” the Doctor intoned. “If the experiment works, the Professor Bennett must die in this universe, and a million others across the multi-verse.”
“I’m aware of the implications,” Bennett answered sharply.
The Doctor turned on him, eyes blazing.
“Are you?” he growled. “I seriously doubt it, sir. You have a child’s understanding of the structure of the multiverse. Do you suppose that it’s only alternate universes you might find? There are layers upon layers of nether dimensions out there, any one of which would be beyond your ability to comprehend. And if you go crashing through the barriers, you have no idea what you might allow through.”
Bennett simply glowered.
“I am one of the finest minds humanity has ever produced,” he raged, stabbing a pointed finger into the Doctor’s chest. “Albert Einstein himself said there couldn’t be more than two people alive who understood the structure of reality better than me. Did he say the same about you, Doctor?”
The Doctor smiled thinly.
“When I said you didn’t understand the multiverse,” he said slowly, “I was talking about humanity.”
Bennett gave an exasperated cry, and stormed away.The machine-gun stood in silence, waiting.