The other Doctor was confused. "I've never even heard of a dimensional current before." she said.

"I've experienced one before." the Doctor replied, "I was travelling through space and time when my TARDIS got sent to an alternate dimension with a different form of Cyberman. For those behind the glass..." The Doctor got out her sonic screwdriver and drew a board with it. "Here's how it works." The Doctor drew two sets of parallel lines onto the board. "The Time Vortex isn't really a vortex in the traditional sense: it is a giant web connecting all points of space and time in one universe. However, there are multiple universes, and thus multiple Time Vortexes. If one part of the Vortex is damaged..." The Doctor scribbled a few lines from one of the sets of parallel lines. "...rather than the usual effect of taking you to a point in space and time, it throws you out of one dimension and into another with immense force. That's the dimensional current."

The other Doctor put her hand up as the Doctor got rid of the board. "What do you think caused this tear in the Vortex?"

"I wish I knew. Until we get you back home, you'll have to stay here in London, except you can't just call yourself the Doctor."

"...because you're this universe's Doctor and it would be confusing. I'll go by the name I have myself in my universe instead: Susan."

The Doctor shed a small tear. "After our granddaughter."

"Right, if I'm staying in this city, who am I going to be with?"

The Doctor turned to the glass. "Jo, is it fine if Susan stays with you?"

"I'll take her in." Jo said through the intercom.

The Doctor turned back to Susan. "She'll take good care of you until this whole thing blows over."

"Thanks! Can I go now?"

"Sure."

Susan left the room as Kate was entering. "Is it possible to create a dimensional current artificially or is it only applicable naturally." Kate asked.

"It's possible, but painful: you'll need a vessel that can traverse the Time Vortex, then you'll need a weapon powerful enough to create a big enough tear in the Vortex wall, and you'll finally need a way to make sure it's sealed back up. All the while making sure you don't get sucked in yourself and also finding the exact right place to make the tear in this case. There's also one more risk to leaving a dimensional current open."

"What's that, Doctor?"

"Potential threats from one universe can see the tear and come into another with malicious intent, although there aren't many beings in the multiverse that can survive being in the Time Vortex in the first place..."

Before Susan was to be taken home, Jo escorted her to a laboratory, where the Rani, a recent hire, was working. "Greetings, Josephine." The Rani said before noticing Susan, "Who is this?"

"I'm the Doctor." Susan replied, "Although, I'm not this universe's Doctor. Jo here told me to come here to test if I am telling the truth on that front."

"Well, you'll just have to take off your blazer, roll up your inner shirt's sleeves, and let me draw some blood from you."

"I can do that." Susan turned to Jo. "You can wait outside."

Jo nodded and went out the door as Susan took off her jacket and rolled up her sleeve. The Rani got out a sterile needle and knelt beside Susan. "This will sing, but only for a bit, alright?"

"Alright."

The Rani took out some of Susan blood and put it into a Petri dish. "How do I know you're not pretending to be the Doctor?"

"Because I remember as clearly as crystal the day I was expelled from the academy: I had barely managed to survive against the Celestial Toymaker, but at the cost of the lives of Rallon and Millennia. I was reprimanded by the higher-ups, including secret CIA member Vansell..."

"...while I was away doing research for the Academy and learnt about your expulsion the day after."

Susan smiled. "Nice to see you again, Ushas."

The Rani held a small closed lip smile. "I don't go by that, anymore. I go by my mother's name: the Rani."

"Shame. Ushas suits you more." Susan noticed the Rani outputting a chemical from one of her syringes onto the same Petri dish as her blood. "What's that?"

"Ryszardine. A chemical I made myself to check whether people are from other dimensions or not. Someone from a different dimension became the basis of this incarnation, in fact: I was in hiding, and then someone who claimed to be a witch ended up crashing into my TARDIS. I managed to take care of her, but not before I conducted my experiments on her, concluding that she was from somewhere that wasn't from this dimension. I took some of her genetic material and created Ryszardine, named after a science fiction author from Poland. After escaping one of my creations, I regenerated into this form, and so it was." The Rani mixed the blood with a silicon rod and saw the colour change in the chemical. "Green. You're not from here."

"So I'm not deluded, then?"

The Rani smiled at Susan. "I guess not." Susan couldn't help but smile back.

In a storage facility owned by UNIT,a small fly-like robot crawled out from the back of Susan's TARDIS. It went underneath the door of the room the TARDIS was in and began to fly out of the building it was in. As it was leaving, it ended up at the car park, where a man noticed the robot and got annoyed. "Oi!" he said as he rolled up the newspaper he was holding, "Get off with you!" As he was about to swat the robot, however, it dodged the newspaper and landed straight onto the tip of the man's nose. Frozen in fear, the man could do nothing as the robot launched its "mouthpiece" forward and it flew off. He looked at his hands and saw that they were beginning to disintegrate into nothingness. He screamed in horror as he was falling apart.

A slightly younger woman noticed the screaming and ran to him. As she reached him, he completely vanished. "Wait," she asked herself, "why was I here again?" She went back to her car like nothing had happened, because in her perspective, everything was fine. This was not an ordinary robot. It was a Temporal Eradicator Fly, an execution tool developed by those who wanted Susan dead: the Time Lords.