Were Carlisle still capable of sweating nervously, he would be doing that right now; as it is, he doesn't manage to completely shake the tremble from his voice, nor the one in his hand to match it.

"N- no I don't- I don't know." Yes, very believable. He goes back to etching, hoping his work will keep his hand from shaking. "Surely it was an accident, though. Who would- who would want to put themselves and everyone else at risk?"

Or just everyone else, if they were an undead who could survive without air.