"No," says Jack, quite firmly, as he picks up his glass.

"I'm going back... up there. Out of here."

Just as soon as he finds a submarine that works, or a bathysphere that'll do more than left, right, select your station and wait for arrival. Guess which station is never an option on those things? Clue: it's a lighthouse.

He gazes for a moment at the glass in his hand, just to make sure that he's not swallowing something awful, but it's actually clearer and richer in colour than the stuff he's been finding around. Back it goes, then.

Yes, the whole finger at once. Without even coughing. Sinclair is going to have to teach Jack some things about moderated drinking for pleasure.