Hannibal detested tardiness, but had been caught up and unable to leave. He expected Nyx to have left as the reception desk was aware of his other appointment and would have sent him away with aplogies.

So he had not expected Nyx sitting there, openly (palpably) using magic, with Alcuin.

"I would advice you not to use magic in open spaces. I trust every vampire in my employ, but I cannot speak for the clients," he said, neutral, somewhat passively aggressive though.