Even from a young age Tom had an unnatural control over his show of emotions, with the exception of his rage which even in later years he had never been able to master. Dumbledore felt some satisfaction with this news, Quirinus wasn't the most powerful wizard or even the bravest so to know the the most powerful dark lord Britain had seen in generations wasn't able to fully possess the man was satisfying and telling of the state Tom had been left in after the fateful halloween night.