The king, seeing how hideous they were, was already frightened at heart; and when he heard the blockhead speak out, he trembled the more, could not keep his seat, and tumbled down from the dragon-couch. Happily the attendant officers were at hand to raise him up.

心驚 = "startled at heart"; 及聽得 (得 = de) = "and when [he] heard." 膽顫 = "gall a-tremble," i.e. quaking with fear; 跌下龍床 = "fell down from the dragon-couch." The king's literal fall from his throne is the comic payoff of his earlier laughing bravado.

So flustered was Tripitaka that he knelt before the hall and, kowtowing without cease, said, 'Your Majesty, this humble monk deserves ten thousand deaths, ten thousand deaths! I said that my disciples were ugly and dared not have audience, for fear of harming the dragon-person — and indeed I have startled Your Majesty.'

慌得 (得 = de) = "so flustered that"; 不住的叩頭 = "kowtowing without stopping." 該萬死 = "deserving of ten thousand deaths," an extreme formula of self-reproach; 朝見 (朝 = cháo) = "to have audience." Tripitaka's abject apology restores the decorum his disciples have shattered.

Trembling, the king came forward and, helping him up, said, 'Elder, it is thanks to you that you spoke of it beforehand; had you not, I should surely have been frightened to death at the sudden sight of them.'

戰兢兢 = "trembling and shaking"; 還虧 (還 = hái) = "it is fortunate that." 諕殺 (諕 = xià, a loan-graph for 嚇, 'to frighten') = "frightened to death." The king's admission — that only the warning spared him — turns his fright to rueful gratitude.

When the king had settled his nerves a good while, he asked, 'Elder Zhu, Elder Sha — which of you is skilled at subduing demons?'

定性多時 = "having composed [his] temper for a good while." 那一位 (那 = nǎ) = "which one" (interrogative); 善於降妖 (降 = xiáng) = "adept at subduing demons." The king courteously styles both boar-monk and sand-monk "elder" (長老, 長 = zhǎng).

The blockhead, with no sense of the fitness of things, answered, 'Old Zhu can subdue them.' Said the king, 'And how do you subdue them?'

不知好歹 = "not knowing good from bad, tactless." 老豬 = "Old Zhu," Eight Rules' self-reference; 會降 (降 = xiáng) = "can subdue." 怎麼家降 (家, a vernacular emphatic) = "however do you subdue [them]?"

Said Eight Rules, 'I am none other than Marshal Tianpeng. Only because I broke the laws of Heaven was I cast down into the world below; and happily I have now returned to the right and become a monk. Since we came here from the Eastern Land, the number-one subduer of demons has been myself.'

天蓬元帥 = "Marshal Tianpeng," Eight Rules' former rank as commander of the celestial river-host. 罪犯天條 = "offended against the statutes of Heaven"; 皈正為僧 (為 = wéi) = "returned to orthodoxy as a monk." 第一會 reads 一 as yí under the mechanical sandhi. Eight Rules' boast — that he is the pilgrimage's foremost demon-queller — inverts the truth (that honor is Sun Wukong's), a self-aggrandizement the plot will shortly deflate.

Said the king, 'Since you are a heavenly general come down among mortals, you must surely be adept at transformations.' Said Eight Rules, 'I dare not claim it — but I do manage to know a few transformations.'

天將 (將 = jiàng, "general") 臨凡 = "a celestial general descended to the mortal world"; 將就 (將 = jiāng) 曉得 (得 = de) = "to manage, just, to know." 變化兒 (兒 = er) = "transformations." Eight Rules' mock-modesty ("a few transformations") sets up the demonstration the king now requests.

Said the king, 'Try changing into something, that I may see.' Said Eight Rules, 'Set me a subject, and I'll change to match the model.' Said the king, 'Change into something big, then.'

試變一個 = "try transforming into one [thing]"; 請出題目 = "please set [me] a topic." 照依樣子 (子 = zi) = "according to the pattern"; 變一個大的 = "change into a big one." The brisk, comic exchange cues the set-piece transformation of the next scene.