There's no shortage of heroes in Gomez Grocery in East Germantown. Yesterday about 12:15 p.m., a tall, 190-pound gunman walked in and announced: "This is a stickup!" With 15 customers inside, the 23-year-old gunslinger locked the door of the store on Walnut Lane near Baynton Street, said Det. Curtis Matthews, of Northwest Detectives. "The man turned around and you could see his gun, pointing at the [customers,]" said a 15-year-old customer, who was buying a smoked turkey sandwich, but didn't want to give her name. "I got down and started shaking real hard," she added. The gunman jumped on the...