It's in his mind now, a plan that surely ends in his own death:

Ascend the stairs. Sink his fangs into the first vampire he comes across. Repeat until there are none left, or until he is dead too.

Louis can't bring his fangs back in, can't reign himself back in. Lestat has him by the shoulders. His eyes are glossy, red traces of tears there. Looking at him, Louis feels some distant, dull stirring of feeling in his chest. An awareness of what had kindled during the trial, the breathless flutter of anticipation at his coming, the love Louis carried for him glowing like a coal in his chest even as Lestat damned him and Claudia both.

"I hate you."

Even this is not enough of anything. Not enough of a condemnation.

But it is assent. Louis leaves the certainty of his own death, and gives over to Lestat's plea.