"As soon as I climbed out, the TARDISes were...gone. They only existed on the inside. I fell onto the ground, eleven feet in the air. I've figured it out now. The outside world is on a different time-stream than ours. Out here, it's October 24, 5629. Inside the TARDISes, however, it's October 17, 5629. The only way that would happen was be if we're..."
"In a parallel dimension!" they said at the same time.
"Our two TARDISes colliding sent us into another dimension. Two TARDISes colliding made so much timey-wimey anomalies that we're in a different time-stream than the outside world!"
"Now you tell me something," said the Ninth Doctor. "How'd you disconnect our TARDISes?"
"Well...somehow...my TARDIS went back online. Rose, Jack, and Clara also moved the TARDIS. We left at the exact same time. It worked."
The Ninth Doctor looked puzzled. "A TARDIS doesn't just come back online for no reason. If you didn't fix it, then..."
"Who did?" said a voice.
The Doctors spun around. The Master was standing outside his TARDIS, giving them his best John Simm grin. "I suppose you would like some explanation?"