It's all AU.

The Master tilted his head back and let the cold winter rain that had just started fall on him, and soak through his wool coat. It suited him, and he was relived that there at least a little weather, in this place, aside from one rainstorm he'd created. He wondered, absently, if he'd accidentally made the rain, if someone else else had, or if had been a bit of a group effort.

He was a little oblivious to the world around him, besides the rain.

Jo was carrying a box of--well, it was hard to say what, exactly. Some of it looked like radio parts, but she doubted that the Doctor was planning on making a radio with any of it. At any rate, she stepped through the door into the lab, saying, "Doctor, Mr. Campbell said this is the last--" And stopped. Not the lab, but somewhere that looked like a hotel lobby. She swung around to look back the way she'd come, and...no door. She took a couple of hesitant steps back in that direction, frowning, and then turned back to face the lobby. "Doctor?" she called, puzzled and starting to get a little scared.

The Master had left the tea shop and gone straight back to his TARDIS, to see for himself what happened if he tried to leave. Once he'd worked out that short hops in space were possible, he'd moved his TARDIS close to the perimeter.

He was standing by the barrier and trying to figure out the best way to analyze it, when he heard someone approach. Well, not just someone--another version of himself. Oh, this day was just getting better and better.