"Clearly," Erik said, as he looked through his carefully constructed Corridors of Death, "I still planned. My promise did not extend to necessary killing, and I left Persia with many enemies who could possibly discover that I was not dead at the bank of the sea. And when I arrived in Paris, there were yet reasons. Midway through the construction of the Opera House itself, a revolution caused some... concerns. There are bones in the Paris Opera House, I imagine, even today."
He hadn't explained, however, why the Corridors were so very well prepared now. The fuel for the fire. The lime. The opened pathways. Hannibal was a wise creature. And yet, he did not expect his dear doctor to know every thought that passed through his mind. Perhaps, in music. But not in this. He clarified.
"The lime was meant for Enigma, should she prove... unmalleable. It would seem that it is no longer necessary to kill her."