Aziraphale stays silent all through Balthazar's staggered reply. There is a small sound of dismay at the confirmation of his worries, and then a long, audible sigh. "Oh, Balthazar. Have you lost your mind? That's Lucifer! First Fallen! What were you thinking? Were you thinking? He could kill you without a thought!"

There's no anger, only a veneer of irritation that doesn't mask the deep, deep worry in his voice. Perhaps a bit of a disappointment, too, like when one hears that their friend has once again hooked up with a malignant ex. This is Lucifer! Balthazar may be a hedonist, but this is well beyond the pale.

"I had to hear about this from his High Chancellor, by the way. Hell is all in a tizzy about it."