Something about being near Armand had always felt, to Lestat, like being near a creature that was barely contained to its corporeal form. His mind and his senses and his powers reaching out invisibly, filling a room, sliding under his skin, lurking in the dark. Lestat did not miss the sensation, shuddering through it now as he bears down.

Probably, it should indicate to him that hurting the body isn't all that effective. But he can't help himself. Hands squeeze tighter, as if he could choke out the glimmering impressions of Louis that don't belong to him. Guards himself with his own memories slipping beneath the surface: Louis sleeping on a New Orleans hotel bed, Lestat watching him from inches away. Louis' smile at an airport carpark, a blur of roses. No sight of Louis in the next, just a series of sensations: his scent, his heart beat, the sense of his arms drawing Lestat in tightly.

A slip into French. "I'm done with you," his voice shivering with his anger. "Whatever punishment you feel I deserve, I've lived it a thousand times, as have those dear to me. You will stay away from my fledgling. You will renounce your own. You will, as you have always been capable, seek out your own happiness away from me."

Does he believe Armand will agree, here and now? No. But it will give context to the shit show that it will trigger. Reason.