(AN) Enjoy!
Rose opened her mouth to answer, but before she could, he had entered the room, somehow managing to convey a sense of authority, and perhaps arrogance, in his heavy, calculated steps. "Of course you know my name, Rose Tyler," he said. He approached her, the Doctor, and with a quick flourish of the sonic screwdriver, snapped the bindings off of her wrist. Alarmed, Rose turned to the Reddolyte who resembled Mickey, but it was frozen. It's hand was raised midair, reaching for some phantom object, and it's lips were shaped in the form of some dead, unspoken word.
Rose turned back to the Doctor, completely unsure of herself and her surroundings in this new development. He was close, and wore a sardonic smirk that fit his face ever so well. "As I said earlier." he intoned in a low tone. "Of course you know my name. Despite my face not being what it used to be, I am the last of my species, exiting the only blue, time travelling phone box in this universe. Who else could I possibly be?"
Rose blinked. "Are you implying... That you aren't him? That you aren't the Doctor?"
The Doctor turned his back to her, walking back to the TARDIS, and shutting the gaping door. "In your head, of course I am," he said softly. "I am always this man, I am always the Doctor, and nothing can change that." He turned to her once more, something darker hidden beneath the gray, pearly surface of his eyes. "Especially so in a universe, created by your very intellect Rose Tyler. For surely, a universe created by your very own mind, could not bear to exist without me."
Rose, on exterior level, only initially recognised the arrogance of this statement. But then, in a short moment's time, the true meaning of what this man was stating settled in. She turned back to the Reddolyte, who still stared at her with unseeing eyes. Observing, without truly understanding.
"I..." said Rose tentatively. "Am still here. I am still in this universe." As the words left her mouth, an infinite sense of dread filled the pit of her stomach, and she felt as though the walls were closing in on her crouched form.
"That... Is partially correct," said the Doctor cautiously. Before she knew what was happening, he stood before where she sat, a pair of spectacles pulled up on his nose, a chalkboard neatly stood at his side. He leaned over it carefully, and Rose could see his arm jerking as he frantically scribbled out some form of diagram. When he pulled away, it appeared that he had drawn a fairly simple display. A smaller circle, and then a line, which extended across the murky green surface to a much larger circle.
"Anyone," said the Doctor smoothly, "Has the ability to form a parallel universe. They are born with it, one could say. Or, not born with it, in a universe where their parents never made the decision, or lack thereof, to conceive them. The point being, there are an infinite number of parallel universes, all constructed on a basis of scenarios that could be, that never were. And then those unfulfilled scenarios themselves have infinite branches themselves, because that is the formation of entropy. A root universe, one could say, collapsing into an infinite string, or tangle, of other universes. However... Not many have the ability to form a root universe, Rose Tyler. Not many have the ability to span across the vast void of empty space and create a whole new root in this tree of possibilities. But... You were presented with the unique possibility to do just so."
Rose stared at him. "What you're saying... Is that here, I have created a root universe?" She asked hesitantly. Her mind was whirling.
"Yes," said the Doctor, calmly. "And from that root universe, an infinite number of other universes branch out. But all of those universes, they are not created through unfufilled possibilities. They are created with your very mind."
A certain silence filled the room, a contemplative silence, in which Rose took a moment to absorb all of the information she was being presented with.
"If this is all in my mind though, this infinite branch of universes... Then how am I seeing you? I have never seen you before in my life," Rose finally inquired.
"Sometimes the mind is a curious thing," the Doctor said, after the briefest moment of deliberation. "I believe, that you and I, are connected on a whole different level. No matter what form I take, you will always know it is me, and I will always know you, no matter who's eyes I gaze at you from."
The corners of Rose's mouth turned down slightly. "But you are not him," she said sadly, slowly. "I don't know if I can ever truly get him back."
"Rose Tyler," said the Doctor, eyes crinkling at the corners. "He is still here. You asked earlier where we were in this instant. And I can state now, that the two of you, are on the same path. Right now, we are at the base of the root. He is in one of the many possibilities, one of the many universes that your mind has created right now. And here, in this moment, you are presented with a choice."
"What choice?" asked Rose, eyes widening.
The Doctor approached her now, and he looked ever so old. Like the weight of many millennia rested on his shoulders. Though that was how Rose had always viewed him. Sometimes even she was capable of discerning this age of his through the perpetual facade of his smiling face. He sat on the edge of the table. Somehow, the Reddolyte was gone now, and only the two of them sat in this room, which appeared to stretch into the distance infinitely, black edges curling into negative space.
"To kill the beetle, or not to kill the beetle," said the Doctor now, his eyebrows arching sharply into his forehead. "If you kill it, you will be returned home. You will be free of this universe in this entirety. But," he paused here, and his eyes took on a certain darkness that made Rose's heart jump in her chest. "You will never see him again. This will be it."
Rose swallowed, but her throat was too dry. She felt as though every molecule in the room was closing in on her, choking her, suffocating her. "What if I don't kill it," she said plainly.
"Then," the Doctor said slowly. "You will stay here. With the Doctor and Jack. You will never see your family again. You will never wake up. Your body will rot and wither away, and as it does so, this universe will rot and wither away with it. Everything you love will slowly disintegrate before your dying eyes. But he will always be there with you, the whole time."
Rose took a deep, shuddering breath, and tears formed in the corner of her eyes. She shut them, and her fists involuntarily tightened in her lap.
"All you need to do is pull the switch in the corner of the room," she could hear the Doctor say in his low, gravelly voice. "You pull the switch, and the beetle is completely destroyed by micro lasers. No pain, but the universe is completely destroyed. I wish you the best of luck, Rose Tyler."
Rose opened her eyes, and gave a gasp of terror. He was gone. The Doctor was gone, and now she was alone in the room. Alone, except for the eternal walls and the bright red lever at the wall, just ten feet in front of her. Rose let out a shriek of a sob, tears stinging her eyes as she clambered off of the table. The whole room swam before her very eyes, and she swayed, her steps uncertain and wobbly. Before she knew what was happening, she was standing before the switch, her pulse roaring in her ears, and her hands trembling.
This was it. She would never see the Doctor again if she did this. And if she would be trapped in this universe filled with phantom not-people, and never see her friends and family ever again.
But she would be with HIM. God, she would be with him every single day. It wasn't until this moment, faced with this decision, that Rose realised how much she loved the Doctor. With all of her heart and soul, with her whole being, she wanted him here so badly now. Tears rolled, endlessly, down her cheeks, dripping onto the cold linoleum floor. Just to have him here one last time, holding her hand, would be more than enough.
Reaching down, she placed her hand on it's crimson surface, and pulled.