With Strange sprawled on the grass, Billie does him the one kindness of not putting a boot on his chest to keep him there. What she does do is crouch down right next to him as she gives him an entirely unamused look. This also has the added bonus of her looming over him real close while he's down there.

"Magic is a part of you, sure. A part that can be ripped away with the right spell," she corrects his earlier words. "That cult that keeps popping up? They can do that. They did it to me. They'll do it to you."

Assuming he ever runs into them but, looking at the City right now, that seems really plausible. She gives a second or two for that to sink in before continuing.

"I had to learn everything I do the hard way before I even touched magic. When a spell isn't going to help me, I'm not shit out of luck for it. So, you can use magic when I say you can. Until then, you hit that target without or you go find someone else to teach you this. You understand?"