When I say he's "doing the S thing", I mean he's raised up, head still, neck stiff in an S position, and he'll follow whoever went up the stairs and walks past his tub. His head only turns when the person is at a 45 degree angle or more. When I feed him, he follows the prey item, too, but won't turn his head unless the prey is some distance from his head.
Right now (I just left my room to check on him) he's totally fine! Just laying there with his head on the paper towel, not moving, completely dormant and docile.