everything unendurable is in the head
What was undealable-with was the thought of all the instants all lined up and stretching ahead, glittering.
Context
The Abiding doctrine generalized from craving to pain to fear — the batch's central insight, arriving as Gately realizes his gunshot agony and his dread of the A.D.A. can be survived the same way the Bird was. No single instant is unendurable; what breaks you is the head's reconnaissance over the wall, the report of all the glittering lined-up instants ahead, news that isn't real yet and that you can choose not to believe. The practical philosophy of the whole recovery plot in two sentences.