The emperor went straight to the banquet table, took up flask and cup with his own hands, filled a golden goblet to the brim and presented it to Pilgrim, saying: "Divine monk — my poor thanks, my poor thanks."

權 means provisionally, for want of anything better, so 權謝 concedes in advance that a cup of wine is not the thanks this occasion calls for. He says it twice. The substance of the courtesy is that he pours with his own hands instead of sending an attendant; the words admit it still falls short.

Pilgrim had taken the cup in his hand and had not yet made his reply when an officer was heard reporting outside the court gate: "Fire has broken out at the West Gate."

聽得 takes dé — after a verb of perceiving, this character has fused into the verb and stopped introducing anything. 朝 is cháo, the royal court, not the zhāo of morning. The report lands in the gap between the cup being taken and the thanks being answered, and everything that follows for the next hundred characters happens inside that gap.