PHILADELPHIA - Chaos, confusion and fear that's how a Jefferson University Hospital nurse, who does not want to be identified, describes the moment workers learned there was a gunman on the loose just after midnight Monday morning."It was hard to figure out what was happening," the nurse said. "We didn't hear any other noises except people yelling there's an active shooter somewhere in the hospital." The employee who was working at the time says they are trained for these kinds of situations but it doesn't make it any less frightening."I was scared because we didn't know who it was, was it a visitor, was it a patient, was it an employee?" the nurse added.