It's plain to see that Superman is not doing well. Most of the color drained from his skin a while ago and not long after that he started to sweat like he was running a high fever. Clark was fading in and out of consciousness, though conscious might be generous. The pain and the radiation poisoning was taking it's toll, and even when he was awake, he wasn't cognizant.

Words were muddled and sights were blurred, but he did manage to focus in on something once he heard it. Slade's voice. No sooner did Slade speak then Superman started moving, sluggishly and weakly, but he was moving, struggling against his restraints.