The Sword and Laser discussion

I am listening to The Peripheral audiobook, and there's a phrase I cannot parse despite listening to it about a dozen times now. In the audiobook it is 1:11 into Chapter 14 of Part 1.

The dialog goes like this:

"Stealing Mr. Zubov's oldest wiskey," said Ossian behind her. "Which I myself secured against oxidation with an inert gas."

Netherton quite distinctly heard Ossian's knuckles crack.

"I ???????????, Mr. Netherton. I've told you that, haven't I?"

This was indeed something the Irishman sometimes said, though at the moment Netherton was entirely unclear as to what it might mean.

Help! It's driving me crazy.

Try using Google Books in the future; I've found it can help with this sort of thing. :)

The paragraph is as follows:

"Stealing Mr. Zubov's oldest whiskey," said Ossian, behind her, "which I'd myself secured against oxidation, with an inert gas." Netherton quite distinctly heard Ossian's knuckles crack. "A pint of plain's your only man, Mr. Netherton. I've told you that, haven't I?" This was indeed something the Irish sometimes said, though at the moment Netherton was entirely unclear as to what it might mean.

Ah, yeah. Good point. Thanks!