占先赴場 First to the Block
一聲傳旨，即有羽林軍三千，擺列朝門之外。國王教：「和尚先去砍頭。」行者欣然應道：「我先去，我先去。」拱著手，高呼道：「國師，恕大膽，占先了。」拽回頭，往外就走。唐僧一把扯住道：「徒弟呀，仔細些，那裡不是耍處。」行者道：「怕他怎的？撒了手，等我去來。」一声传旨，即有羽林军三千，摆列朝门之外。国王教：「和尚先去砍头。」行者欣然应道：「我先去，我先去。」拱着手，高呼道：「国师，恕大胆，占先了。」拽回头，往外就走。唐僧一把扯住道：「徒弟呀，仔细些，那里不是耍处。」行者道：「怕他怎的？撒了手，等我去来。」
逐句解 Line by line
At one word of the decree, three thousand of the Plumed-Forest Guard were ranged outside the court gate.
羽林軍, the Plumed-Forest Guard, was a real imperial bodyguard from Han times onward, and three thousand of them are a lot of soldiers for one small monk. 擺列朝門之外: 朝 = cháo, the court gate.
The king ordered: "Let the monk go first to have his head cut off."
國王教: 教 = jiào, ordered. Monk first.
The Pilgrim answered gladly: "I'll go first, I'll go first."
欣然 is "gladly, with a will" — nobody has ever gone to an execution this cheerfully. 應 is yìng here, to answer or accept, not the yīng that means "ought."
Cupping his hands, he called aloud: "National Preceptor, forgive my boldness — I take precedence."
He cups his hands and begs pardon for going first, as if the block were a doorway and he were being rude about precedence. 占先: 占 = zhàn, to take precedence. 拱著手: 著 = zhe.
He jerked his head round and made straight for the gate.
拽 is zhuài here, to jerk or yank — this reader's standing reading for the character, against the zhuāi that automatic tools default to. He wrenches his head round and goes.
The Tang Monk caught him fast and said: "Disciple, ah — be careful; that is no place for fooling."
那裡不是耍處 — that is no place for fooling. Here 那 points: nà, that place over there. 仔細些: 仔 = zǐ in 仔細, careful. The master is holding his sleeve, which is what he does.
The Pilgrim said: "What's to fear of him?
怕他怎的 — what's to fear of him? Five words, shaken off like a hand.
Let go your hand, and let me be off."
撒了手, let go your grip; 等我去來, let me be off. The exchange is the pair in miniature: love offered where it is not needed, and shrugged away without unkindness.
Wukong turns the execution ground into a stage before he even reaches it. He insists on going first, cups his hands, and begs the National Preceptor's pardon for 占先了, taking precedence — treating his own beheading as an honour he is rudely claiming ahead of a senior. Tripitaka, meanwhile, has hold of his sleeve: 那裡不是耍處, that is no place for fooling.
The exchange is the two of them in miniature, and it recurs the length of the journey. The master, who can only see the visible danger, grabs at his disciple; the disciple, who alone knows what he can survive, shakes free with a careless 怕他怎的. Both the love and the power are real, and in this moment they are pulling in opposite directions — protection offered where none is needed, which is one of the kinder jokes in the book.