This is fascinating...

Sheldon Whitehouse is leading Ali Soufan through questioning. What Soufan is saying is that when he used lawful interrogation techniques agaist Zubaydah, he got actionable intelligence within an hour, including the identification of Khalid Sheik Mohamed as the mastermind of the 9/11 attacks.

However, when a contractor came in and began using harsher techniques, Zubaydah clammed up. It became clear that Zubaydah had received training on how to resist torture.