What I wish would happen right after the preview…
The man – the other Doctor – stared for a long moment at the thing. The Doctor noted that he narrowed his eyes first at it, then at the screwdriver in his hands. Then, a slow smile broke over his face.
"Right then!" he grinned, and jabbed forward, ramming it forwards. He pressed a previously unseen button and a high pitched whirr ran through the Doctors ears. His own screwdriver remained in his hand, unused. The creature screeched, and ran. Wasn't that a Cyberman head…?
The other Doctor smiled, and the Doctor noted is semi contemporary clothing (although just a little too colourful to be accurate) and devilish smile.
"Right then," he said to the Doctor, and smiled. "Who are you, old chap?"
"Er…" the Doctor said, at a loss for words.
"He says he's the Doctor," Rosita put in. "Just the Doctor."
The other Doctor looked him up and down and made a face of slight confusion mixed with doubt mixed with comprehension. Then he smiled.
"I see. Tenth?" he asked.
"Yeah," the Doctor said, bemused. "Tenth."
"Well," the other Doctor smiled. "That explains everything then! Now, come on!"
"What?!" the Doctor said, confused.
"Oh do keep up old chap…" the other Doctor said reprovingly. "This confirms my theory Rosita!"
"What theory Doctor?" Rosita asked.
"That we came through a gap between dimensions into a parallel world!" the other Doctor said. "Yes, of course…"
"A gap between dimensions?" the Doctor put in.
"Yes, I thought it was rather odd," the other Doctor said. "But anyway, no dawdling… come on!"