Professor Grouse didn't know about Vile. Probably didn't even know Vile was significant. Erskine nodded curtly back at Wreath, then gently guided Anton over to where the Professor was pointing.

Something else he couldn't decide on his feelings about. The Professor not knowing meant that Skulduggery - and, in particular, Corrival - didn't intend to make it widely known, and therefore didn't intend to do anything about it. On the other hand, the Professor not knowing meant that anyone knowing at all was not what they'd intended. Wreath certainly shouldn't have found out. Corrival would probably want to keep this close to home. Erskine could respect that, at least, even if he couldn't understand anything else about the whole thing.

Least of all, how and why Professor Grouse wasn't more moved in some way about having an angel for a patient.

"He nearly lost control of his Gist," Erskine explained quietly. He tried not to wonder how much internal damage there was. He wasn't a doctor. Even so, Erskine didn't mind hazarding a guess, given that he was still a little shaken over what might have happened if he hadn't shown up. "There's probably... he was coughing up blood earlier. It made a mess of him."