In the beginning of the chapter, Dr. Manette tells us that she doesn't believe that she signed the unequal agreement. She says that she can't stand to watch her friend die like this, and that she'd rather have half her liver than half her friend's liver. He says that half a liver is a lot better than nothing, and he'll marry her and care for her for life if she needs it. He's a doctor, after all, so he knows what it's like to have a patient with a life-threatening condition. He tells her that he's sorry to see her go, but that he has to find a way to save her life.