The double may have been full of lies, but the fear that crosses him just before Glacius knocks him out is absolutely authentic. As for the real Carlisle, he sounds relieved beyond measure when the alien returns to the phone.

"Glacius," he answers. His voice is hoarse, weaker than it was before, as though the comfort he feels from knowing his dear friend is safe sucked the fight out of him. "Thank the Clarity that he- he didn't—"

A choked sound escapes him, one laden with the torment he feels both physically and mentally. The shears impaling him are bad enough, but the thought the double might have compelled Glacius to hurt himself was a torture more than he could bear.