Kate concussed after the purse-snatch — "Kate Gompert couldn’t summon the juice…"
Kate Gompert couldn’t summon the juice to tell him to go screw. That’s the way it was said down here in the real city, Go Screw, with a deft little thumb-gesture. She couldn’t even say Go Away, though the smell involved in the man made it worse, the nausea.
Context
The "witness" bum looms in with his palm out, and Kate can't produce two words in her own defense. "Couldn't summon the juice" is the book's Kate-specific depression idiom — the Ennet House narrator used it about her at p. 206.