There's a LOT Ifrit could reply with. That she won't walk for much longer without treatment. That she won't live for much longer without treatment. That even if she did, hey maybe this guy would love to live with the chronic nerve pain and hallucinations.

Or, she could not do any of that, because it'd make her look weak and lame. "Okay, then kill me later when it gets worse. Happy?" She chucks the book in his direction. Watch out, it's a heavy book.