I thought about that after I wrote it - but really, how would he be able to do anything? Unless they do what they did with Spooks last year, and kill the main character off in the first episode so other characters could carry the rest of the season. But I can't see them doing that with Jack because he's the money star. And no one's going to want to make/watch a series with him losing his mind and having convulsions every five minutes.

Plus, this is JB we're talking about. Bet you any money he'd eat a bullet before it got that far.