A heavyset Hispanic woman — seen by five witnesses pacing and mumbling to herself — pushes a helpless man in front of an oncoming Flushing-bound No. 7 train in Queens. She was caught on tape while fleeing the crime scene: police. A MAN WAITING for an approaching No. 7 train in Queens died a gruesome death Thursday night when a young woman darted up behind the helpless straphanger and pushed him onto the tracks, police said. The unidentified victim was crushed by the first and second cars of the Flushing-bound train about 8 p.m, as his murderer hustled down the...