"Hand over the purse, lady."  It's a gruff voice out of the night, a threatening bark that leads me to gasp and start involuntarily even though I've come down this forbidding road intentionally in a quest for my unusual brand of fun.  It's an adrenaline shot through my whole body, like boiling water through my veins.  It's time.  I hug my purse protectively closer to my rib, and slowly revolve to face my assailant.  He's there in the yawning shadows between the two dim streetlights, the knife edge a gleaming ribbon in the dark.