Could you explain "drain her to the sump"? What does it mean?
The phrase is from Gut Symmetries by Jeanette Winterson:
I imagined her, angry, confident, ready to match me and beat me at my own game. This was the big fight and Jove the prize. . . I had dressed as a warrior: black from cleavage to insoles, hair down, fat hoops of gold in my ears, war-paint make-up. I had a twenty-year advantage over my opponent and I intended to use every month of it. She would be greying, she would be lined, she would be overweight, she would be clothes-careless. . . I could see her, hair and flesh escaping, hope trapped inside. I would drain her to the sump.
I can see it's a threat, a metaphor probably, but I can't catch the exact meaning. "Empty"?