“Gabriel” opens with a shot of a winter landscape just before dawn, its stillness suddenly shattered by the roar of a bus speeding across the screen. A young man in a woolen watch cap and winter coat gazes out the window. He tries harmlessly to engage a little girl who is grinning at him from several rows away. She finally joins him, and they are pretending to be smoking Twizzlers when the girl’s mother rushes up the aisle, snatches her daughter, and drags her back to her seat.