So obviously he's composed about pain. What we really need is a long form torture and leave him alone for a while so he can't vent frustration at you. Chinese water torture isn't very exciting, but can induce panic and high emotion. He's sassy and refusing to engage will infuriate him

(understandable if you're not into writing this, not very exciting)

You wish you had more time to work on this guy. You're sure if you could just find something to amp up the fear, you could break him thoroughly.

But alas, you don't have that luxury. If you can't produce some results soon, your superiors will likely take the job from you, and classify it as another one of your failures.