"Nothing at all, one would hope. But I don't think I'd trust our captors to return us to the moment we left just because we want to return."

Not least because they seem to be the types to look for any loophole to their benefit they can find. They weren't above trapping a bunch of people here; they're not going to let anyone go without a fight.

Still, Haru very much does understand the problem with Dr. Maruki having that kind of power. Wanting to help people overcome their pain is one thing; warping reality to remove it is quite another.