His humming didn't stop as he responded to her, the tone of his thoughts coming in tune with the song he was murmuring as he worked. As are you, Sadako.
He worked on the tail of the Phoenix last, the cutting away of her skin had to be thin and precise in the details there, and he was looking very consumed by his job at that point, not scowling or depressed in any way. It was a look of concentration, but also of satisfaction. His job was almost complete, this work of art was nearly done. A few bits of skin later, he wiped the blood off the newly formed wounds on Sadako's body and admired it. "Lovely. Yes, that is the word for it."