Tom was someone who almost always controlled his emotions and the gripping of his armrests was one example were his carefully crafted veneer cracked. However, what could have been frustration for allowing it to be shown, was minimised by Lestrange's reaction. She shrunk away from him, even if she knew he could not utilise his magic. It was fear of his power and Tom was certainly pleased with that reaction. He would have to further research his reputation to determine just how much power he would have over others.
Despite hearing about Potter's alleged role in his original downfall, a fascination to meet him was already developing. There was clearly something important about him and Tom was interested to discover exactly what it was. "Good, gather the books you original used and bring them to me at the first opportunity," he almost ordered in a more authoritarian tone. He had behaved as such around his followers at Hogwarts, but as Lestrange continued her speech it seemed to indicate that he had the authority to issue such orders and she would listen. Exactly what he desired.
He observed her mannerisms carefully, noticing how she twitched and seemed unwilling to continue. He listened to her words and watched her reaction examining that she almost seemed upset. However, he did not care about her feelings. He turned away from her and stared at one of the opposite walls. She must be lying or misinformed. It was impossible that he could have died. Cementing that as his current thought, after a few moments he turned to her again
"Admittedly I find some of your tale difficult to believe Mrs Lestrange."