A gunman brandishing an assault rifle opened fire on drivers in Cambridge, Massachusetts , Monday, leaving two people with life-threatening injuries. The shooter discharged his weapon at cars and into the air along Memorial Drive – which runs parallel with the Charles River, not far from Harvard University – at approximately 1.20 p.m., causing panic on the road. Drivers were forced to abandon their vehicles and flee, as a huge police response quickly swarmed the area. Authorities said he discharged between 50 to 60 rounds during the incident. One witness, Joseph Minino Rodriguez, said he saw the shooting unfold from his apartment balcony overlooking the road. “I thought this was a video game,” Rodriguez told reporters. “He didn’t give a f***.…