您不了解他们的心态。他们不会接受您的辞职，因为他们认为您没有辞职的权利。他们是决定您应该停留多长时间以及何时应分配的人。最重要的是，这种任意性变得难以忍受。
(You don't understand their mentality. They won't accept your resignation because they don't think you have the right to quit. They are the ones who decide how long you should stay and when you should be dispensed with. More than anything else, it was this arbitrariness that had become unbearable.)