1. If you are the only thing stopping them becoming toxic to engineers, they will eventually, regardless of how hard you fight. 2. You have an obligation to yourself to keep yourself healthy, not this company. 3. THEY DON'T DESERVE YOU.
I can't emphasize the last point enough. If you are the ONLY thing stopping them from self-destructing, they deserve to self-destruct. Your preventing them from turning toxic doesn't change the fact that they are predisposed to toxicity. They're crappy company and they deserve what they get.