Micah knew when the Blue Velvet went up in flames. It was impossible for him not to. So he was on the move even before receiving Ariel's call, making several more of his own to ensure that he had enough Ventrue around the perimeter, opening up temporary shelters for the Kindred displaced by the fire and having a supply of blood opened up to be shipped immediately to ground zero for the wounded on the spot.
Much later that night, when someone informs him that Anastasia doesn't make it out of the building, Micah doesn't move or say anything for the longest time.
When he finally does, he orders everyone out of his office and rejects all further calls and visitors for the night.