(Don't knock out the one of them that can control his mind enough to alter his surroundings, Hayley.)

Bruce looks wary, but willing. "I guess we can't stay here forever. I don't know about... relative passage of time." A brief shake of his head. "We can try. It might go disastrously. Be prepared."

It's all a lot like meditation for him, just a more functional, active kind. Which he has to employ anyway in order to get through his days with the kind of equilibrium he espouses, so it's not anything new for Bruce. It just has drastically more tangible results.