Due to Tarn's part in kidnapping Sonia, his known murderous tendencies and violent past, and the fact that he is by far the single most unpopular outsider with literally everyone, Tarn loses 10 LP for his defection to the Barrayaran side, putting him at 18 LP. What little new information Piotr gets from him during torture doesn't really make up for it, unfortch.

SORRY TARN YOU'RE THE WORST