I just tried this myself and nothing much happened other than a Female Tourist killing herself on... something in the pile.
Then again, it WAS raining if that actually changes anything. I'll go run a few more tests.
EDIT: Waited for about 7 hours of in-game time and nothing blew up or caught fire. I think what probably happened was something or someone around New Attnam walked over and set off something while Zayre was waiting around, if I had to guess.
This was on the latest build, 0.50.4
Could also be if Zayre was using one of the older builds? Like the one where entire dungeons used to catch fire by accident?
...You know I suppose the holy banana of oily orpiv and any flaming weapon probably should
start burning things on the same tile. Not the floor though or we get the burning dungeon problem again.