James still has his knives on him, so that's always an option. It's not ideal, and he doesn't really feel like taking his chances by releasing his hold on the wall even partially, but if getting squeezed to death is the alternative, then he's not about to go down without a fight.

"Why? Are you timing me?!" Rhetorical, really. He's not sure what the guy's thinking, but figuring there's a plan in there somewhere, he nods. "Fast! Now!"

What, he's not about to wait. With that, he starts climbing faster, taking the opportunity that he's not currently trapped. It's less secure and precise like this, there's a good chance he'll slip up somewhere, but he's up for the challenge.