The woman was absolutely and utterly mad. There was no other explanation. But if playing along with her delusions was the only way of preventing her from burning the forest down around them- he didn't trust the Elementals to not take offence at even an illusion of their domain being thus attacked- then he would do it. "Wait!", he shouted. "Deal with the beasts you've angered- without burning down the forest-, and I'll tell you what you wish to know."

And hopefully he'd have figured out what that was by the time she'd finished off the Treants and Ziz. Meanwhile he was still keeping a healthy distance from her, ready to break and run if she decided to ignore him.