A hail of bullets greeted a 20-year-old man after he bought a ginger ale and stepped outside a Brooklyn bodega Saturday — sending the mortally wounded victim scurrying back into the store.Donovan Frazier’s final moments were captured on a dramatic surveillance video inside the Franklin Finest Deli on Franklin Ave. in Crown Heights.The video shows Frazier standing by the front door as bullets suddenly start whizzing inside about 4:20 a.m. The suspected gang member rushed back inside, clutching his chest as two deli workers hit the floor for cover.Struck multiple times in the chest and stomach, Frazier crawled to the back of the shop where he was found covered in blood.