He was keeping his back to the wall, if anyone looked at his back, he'd die. He can't do anything about it, since [Cheap Trick] would kill him if anyone saw him, because he was attached to his back

Rohan: "Damnit..."

Cheap Trick: "Come on! Burn those pictures!"

Then he saw you, and he moved his back to the wall. He couldn't tell you why you can't look at his back, just that you can't.