The Four Noble Truths are the truth of suffering, the origin of suffering, the cessation of suffering, and the path leading to the cessation of suffering.
Why is the doctor analogy used in relation to the Four Noble Truths?
It illustrates the process of diagnosing suffering, identifying its cause, recognizing the possibility of its cessation, and prescribing a path to achieve that cessation.
Gethin shows Nibbana from three points of view: extinguishing the three fires, the condition of a Buddha after death, and the unconditioned realm known at the moment of awakening.