Long past evening rush hour on the Monroe Street subway platform, Sam Kelson listened to a woman playing an electric guitar and singing— You’re awfully cold around the hot— You freeze me when you touch that spot. A crusty amp-and-speaker combo made her music sound as dangerous and true as an old razorblade. Kelson grinned and started to dance. The singer looked eighteen but could’ve been thirty, the way that living on the streets can strip years from rare individuals instead of aging them. She wore faded blue jeans and a startlingly white T-shirt. Her face was thin, her teeth