A decorated Boston plainclothes cop dove through the window of a fleeing SUV, trying to take control as the driver took him on a harrowing 100-yard ride Sunday night, with half his body hanging out of the vehicle, police said.Officer Clifford Davis and his partner officer Christopher Kennedy had just pulled over a speeding, weaving Nissan Murano and asked for the driver’s license and registration when, their report states, suspect Bryant Gilbert said, “(Expletive) that, I ain’t doing this.”