An employee allegedly shot and injured three co-workers at a Smile Direct Club manufacturing facility in the Antioch neighborhood of Nashville, Tennessee, early Tuesday, officials said.One worker was struck in the chest, one in the abdomen and one in the leg, Nashville police spokesman Don Aaron said at a news conference.One of the victims is in critical condition, he said.The suspected gunman, a 22-year-old employee, left the building as officers responded to the call, but officers spotted him at an intersection and demanded he drop the weapon, police said.The suspect, armed with a semi-automatic pistol with an extended magazine, instead...