"I beg your pardon?" Strange can't help but respond, honestly confused as Childermass mentions doing the spell for an audience. Well that makes no sense. The audience, why would he do any of this for an audience? Then the pieces connect and he makes a noise of recognition, before shaking his head.

"Oh, no, this isn't for the audience. This is simply to see if I could do it." But since Childermass isn't coming over just yet, Strange is going to just keep pretending that nothing's wrong, that the spell worked perfectly, as he looks down at the puddle as if he can see things that aren't his reflection.

"A man under a hedge sold the spell to me back at Shropshire," just said nonchalantly as if men under hedges make perfect sense. "I took it, I performed it, it worked. I decided that was reason enough to become a magician."

But why isn't he coming over...ah. And then Strange realizes, of course Childermass is staying over there, he doesn't know that Norrell counts as Strange's enemy (although really, who else would it be? The man destroyed his book, after all) ergo he's not interested in what's happening at the first place. He probably thinks Strange's enemy is Drawlight or someone else. Well, time to attempt to draw him in further. Strange wrinkles his nose as if spotting something distasteful, looking down at the puddle again while trying to keep Childermass in the corner of his vision.

"And there he is, talking with Lascelles again," just said a little bit too casually. "I honestly don't see what Norrell sees in that man."