The Doctor was the first one to move, slowly circling around the console. Tapping on every button, pulling every lever, staring at every monitor, it became increasingly clear that all power to the TARDIS was gone.
"How is this possible.." He said to himself, double checking and then triple checking everything. His jacket had been buttoned one of the trips around the center, but it wasn't apparent how that had happened. Clara had gotten up after swallowing her lunch once again, and was leaning against the outer railing, slightly nauseous. Her long brown hair had been completely swept over her face during the violent shaking, but she had not even bothered to fix it. Brown eyes stared at the Doctor for the first two circles, but at the third, she gained enough control to speak.
"What in the name of God just happened?" She said, moving into the Doctor's path so he could not make a complete third trip around. He stood in front of her, contemplating just walking around and skipping the few buttons that she blocked with her body, but decided against it.
Sighing, he put a fist against his head and said, "Well, it appears as though there was some interference during our jump to Dusseldorf. The interference was something that this machine had never experienced before, which is why it was sent into such a violent mood. Whatever it was that was pulling as in has stopped, though I am afraid of what lies outside of the doors. It could be something extremely peaceful or we could be walking head first into an army of Daleks. I don't know about you, but I would prefer not to spend my last breath as a free Time Lord staring into an eyestalk of one of my mortal enemies."
The Doctor stood there, looking at Clara, waiting for a response. When she did not give one immediately, he simply sighed and moved around her, giving the buttons one final check. However, nothing even changed in the slightest, and it made Clara start to laugh. The laugh started out as a silent giggle, but soon the noise was filling the entire room. The Doctor, having stopped in his tracks when he first heard the laughter, was now once again standing in front of Clara, a facial expression that radiated puzzlement as well as anger.
"Why are you laughing so hard? This is a serious situation!" The Doctor said, his mouth downturned slightly in a frown. He was genuinely confused why the brunette would be laughing at something quite like this.
Clara, composing herself, "You are insane, Doctor."
That remark was one that the Doctor heard throughout his entire life from various people. Whenever he would show them his time machine, they called him insane because it was bigger on the inside. Whenever they would see him pull out a sonic screwdriver (or some other tool, during those incarnations where he didn't use one), people would call him insane. Even alien species like the Daleks, Sontarans, and other Time Lords have called him insane. It had never got to him, though, until it was said to him through the voice of a certain Clara Oswin Oswald.
"Please enlighten me as to how I am insane," The Doctor spoke coolly, even though his face retained an expression of anger.
Clara, laughing again, "The definition of insanity is doing something again and again, but expecting a different result."
That is when it clicked for the Time Lord, and he spoke, "And since I have been checking all of the buttons and levers, expecting them to work, that makes me insane. Huh, I guess I had never thought of it that way. I also suppose that I should be focusing on the real matter at hand, and that is why all of the power is drained from the TARDIS. There is only one way that could be, and it is almost impossible." Nonetheless, the man started making his way towards the outside door.
Clara, following right behind him, asked, "Didn't you say it may be dangerous, whatever is behind that door?"
The Doctor turned around and said to her, "You know the Cybermen, right?" Clara nodded, so he continued, "Well, they all run on electricity, as they are machines. Their entire home planet, which has been inhabited by these machines for a million years to the day, was drained of all of its natural energy in order to run the Cybermen and help them thrive. However, as a means of population control, so to speak, the planet started to take energy from the Cybermen in order to keep its structure, which kept the Cyberman population stagnant. The planet also took energy from any new machines that got near it, and if my suspicions are correct…" The Doctor opened the door.
"Welcome to Telos, the original planet of the Cybermen."