That's... the Doctor isn't even sure what to make of that. "Tell you what, let me go fetch you're payment and I'll meet you there."

After all, wouldn't good for the TARDIS to become noticeable. He meets at the place a few minutes later. He holds up the bob and presents it to Kinner.

"There you go, paid in full. Now, about that... alien eating you... How do you know that... you're you?"

The Doctor has is own existential crisis he's dealing with, so, why not poke holes at other's? Might help him.