He's frusterated by the whole situation, but Tarn tries not to hold it against Deanna-- just as he had not held it against Pearl.

"Yes, my point exactly. They should not act with such discrimination when they have a perfectly willing volunteer." Tarn knows that the whole business is rather dubious, but he's desperate for even a fraction of his powers back. He could bring the Cetagandan base crumbling down. Still, knowing exactly what sort of beast he's dealing with will help. Thanks to Pearl's input, he's already begun to piece together a picture.

"Might I ask what your reason was for declining?"