回身救師 Returning to Save the Master
行者在半空裡聽得明白，他想著：「師父不濟，他若到了油鍋裡，一滾就死，二滾就焦，到三五滾他就弄做個稀爛的和尚了。我還去救他一救。」好大聖，按落雲頭，上前叉手道：「莫要拆壞了布漆，扎我師父，還等我來下油鍋罷。」行者在半空里听得明白，他想着：「师父不济，他若到了油锅里，一滚就死，二滚就焦，到三五滚他就弄做个稀烂的和尚了。我还去救他一救。」好大圣，按落云头，上前叉手道：「莫要拆坏了布漆，扎我师父，还等我来下油锅罢。」
逐句解 Line by line
The Pilgrim, up in the air, heard it all plainly and thought to himself: "My master is not up to it. If he goes into the oil-cauldron, one boil and he's dead, two boils and he's scorched, and by three or five boils he'll be a soft-boiled mush of a monk.
The reckoning is done in the flattest possible arithmetic, which is what makes it awful: 一滾就死，二滾就焦，到三五滾… one boil and he is dead, two and he is charred, by three or five he is 稀爛的和尚, a monk boiled to mush. 聽得明白 takes the linking 得, de; 他想著 takes 著 as zhe. 不濟, not up to it, is the same phrase he used about his master on the road.
"I had better go and save him."
And then, without any fuss at all: 我還去救他一救. I had better go and save him. 還 here is hái, "after all, I suppose I had better" — a word that carries a small shrug, as though the decision were obvious and slightly inconvenient.
Good Great Sage! He brought down his cloud, stepped forward with hands folded, and said, "Do not break open the cloth and lacquer to scald my master—just wait, and let me come and go into the oil-cauldron."
好大聖, "Good Great Sage!" — the storyteller's applause, and for once it is not for a trick. 叉手, chā shǒu, is standing with the hands folded together, the posture of someone making a formal request. 莫要拆壞了布漆, don't break the cloth and lacquer open; 扎我師父, don't put my master in the pot. 還等我來下油鍋罷, wait for me to go into the oil instead, with 還 as hái.
He is safe. He is in the clouds, out of reach, with the whole west open in front of him, and every practical consideration says keep going. The novel gives him one line of reasoning — his master will not survive the oil — and one line of decision: 我還去救他一救, I had better go and save him.
The word 還 is doing the work in that sentence. It carries a shrug: after all, I suppose I had better. There is no speech, no struggle, no announcement that he has chosen loyalty over freedom. He simply comes down, folds his hands, and asks them to put him in the pot instead of the old man.
This is what the chapter has been for. The golden band, the tightening spell, the whole apparatus for compelling a wild creature to behave — and when the moment comes none of it is switched on. Sanzang could not recite the spell if he wanted to; he is wrapped in lacquer with his face showing. Wukong comes back anyway.