“Finally!” the Doctor’s laugh echoed against the concrete walls. The remaining four looked at him in shock. “I mean, how long does it take for you humans to kill each other? I had to help you along obviously.”

“The needles?” Katya questioned. “Th-that was you?”

“Of course it was me!”

“So, you got the needles at the hospital where you work?” Jeremiah inquired, then corrected himself. “Worked.”

“Look, I haven’t got time – nor can I be arsed – to explain my actions like some film supervillain. All you need to know is—”

There was a large boom as the four remaining humans disintegrated leaving piles of ash covered in grubby clothes.

“Oh, come on!” the Doctor yelled at the concrete ceiling. “I wasn’t done.”
Technically you should be looking down.
“Okay, whatever, where’s my TARDIS then?”

Satan rose from a pool of lava that had appeared on the floor and threw a key to the Doctor, who scrambled to his TARDIS like a mongrel. “To think,” Satan pondered. “You sent me into a black hole and now I own your soul.”