What does "the old lady borrows the fire" mean in Dragon Eight Branches?

The old woman wanted to help Duan Yu and them, but her kindness was misunderstood.

The story of "the old lady borrows fire" in Eight Dragons;

Seeing that there was no Duan Gongzi among the people, the old woman tricked them into burning knives and striking flint, so that we couldn't light oil lamps. The handmaid covered all the couplets on the pillars with straw mats to avoid attracting intoxicating bees into the house. Who knows that these people insisted on asking for it, and finally got angry and saw the couplets.

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Duan Yu breathed a sigh of relief and thought, "Who am I? It turned out to be dad's other old lover. She came to see her father's bad luck, but she was just jealous. Yes, she arranged to poison the bees. Originally, she wanted to catch dad, but she taught me wrong. In that case, we are determined not to kill him. But who is this aunt? I must have heard her talk. "

Mrs. Wang said humanely, "I have kept this nest of bees for more than ten years. I gradually add anesthetic to the honey that bees eat, and then add another medicine. After this intoxicating bee knocks people out, it will knock them down and make them unconscious for four or five days. "

. . . .

Duan Yu suddenly realized: "It turned out that many calligraphy and paintings lacked pens and words along the way. Mrs. Wang led my dad to fill it out. He filled it out well. People who are ambushed by Mrs. Wang know that he is a prince of Dali Duan and will send wine and rice doped with drugs. "

Mrs. Wang said, "The oil for lighting in the wooden house is pre-loaded with medicinal materials. I hid the medicinal materials in wooden pillars. The little devil broke the pillar, and the aroma of several herbs mixed together, attracting intoxicating bees to enter. Well, my plan is completely correct, but the person who came is wrong. This kid ruined my activity! Alas, if I don't cut him into seventeen or eighteen pieces, my hatred will be hard to vent. "

Duan Yu listened to the tone of her hatred, so scared.

I heard Mrs. Wang hate and hate again and again, saying, "I want this handmaid to pretend to be a deaf-mute old woman and take charge of the overall situation. It's not that she doesn't know that man, and finally she made such a big joke. "

Mrs. Wang snorted and said, "In a word, you are useless."

Duan Yu said, "The old woman tricked us into flint and wrapped the pillar with a straw mat. It turned out to be good for us, which was really unexpected. "