article_snippet.sent: Boston Police Superintendent-in-Chief William Gross, (center left), walks through a revolving door as Boston Police Superintendent-in-Chief William Gross, (center left) departs the Shapiro building at Brigham and Women's Hospital on Tuesday after the shooting .
article_snippet.sent: Medical personnel walk past law enforcement officials, (right), as Medical personnel depart the Shapiro building after the cardiologist was shot .
article_snippet.sent: The FBI, Boston Police Department and the ATF all arrived at Women's Hospital after the incident on Tuesday morning .
article_snippet.sent: Shortly after the shooting, one witness said that the Shapiro building had been placed on lockdown and dozens of emergency vehicles had arrived on the scene. '
article_snippet.sent: Once the Shapiro building had been placed on lockdown and dozens of emergency vehicles had arrived on the scene were clear of an exam room with the weapon, there were police officers with their weapons drawn yelling, 'Get down!
article_snippet.sent: Hospital employees are well-drilled for the nightmare scenario of a shooter inside the Shapiro building.
article_snippet.sent: In November 2013, doctors and nurses and other staff at the world-famous institution underwent training for an active shooter situation and viewed a video for a so-called 'Code Silver' event.