Klaus has his eyes closed, but he opens them just so he can see the part where his vision starts to go out from James's hand on his throat. Most people aren't all that willing to go for this; thank god he judged this right.

Finally, when he can hardly catch his breath, he comes, rasping James's name out as best he can, both hands braced against the wall. It doesn't even matter to him if he passes out, or what happens. The drugs and the sex and the kink are so good, and he doesn't have to think about anything else, which is just what he wants, like some ultimate goal.