The dog is ill. Painful disease, horrible, so agonizing that he wants to die. But there's a cure for this now? No, he'll have to suffer for weeks before getting better. Don't die, don't die, I love you so much! Your arms around him. You discuss it with him. Although the pain is horrific, he's able to converse rationally. For your sake, he agrees to live, an act of heroism given the depth of his suffering.