Stay: Rising to the occasion could reward you, especially if you agree up-front (in writing!) that there will be a pay-off when things let up. Come up with new ways to do things that conserve time, energy and money for you and those around you. If nothing else, when the time comes, those achievements will stand out on your resume.
Leave: Consider which of these will last, your nose or the grindstone? Every good employee wants to go above and beyond, but when that becomes the new "minimum standard" you have to realize you already have a new job, like it or not. Save your nose, keep an eye out for something better.