HE WEARS A black hoodie to protect himself from the cold rain. The baby-faced guy is Dominican, probably in his early twenties. He rushes by me at the Graham Avenue L train entrance, pauses and asks, "Matt?" I nod. He leads me down the stairs, examines me silently. Once he's satisfied that I'm not a threat, he takes $30 from my left hand and pushes a sealed bag of Cheez Doodles into my right jacket pocket.