"That's what he SAID, yes - but did he really? "
Wouldn't suprise me if he did, since he was apparently trying to isolate Jack. Could have been the other person we saw at the end, too. But I gather you've read the synopsis, so maybe I'm wrong on one count or another -- or both.

(Don't tell me if I am wrong or right, please.

)
BTW, we get a double dose of John on Saturday night, as he's in the Dr. Who three-part finale that airs starting at 5 p.m. EDT on BBC America.