For hundreds of employees at 345 Park Avenue, an iconic 44-story skyscraper in the heart of Midtown Manhattan - a neighbourhood packed with offices of major corporations - Monday evening suddenly became like no other.
As commuters made their way home on the sweltering July evening, workers at the Park Avenue tower ran for their lives, barricading conference rooms with tables and sending loved ones pre-emptive goodbye messages.
"I texted my parents, 'I love them,'" Jessica Chen, who works on the second floor, told US media. "Nothing can describe that feeling."
Ms Chen and others in the skyscraper were spurred to action by the unexpected sound of gunshots coming from the lobby.
The gunfire would kill four people, including a New York police officer, as well as others in the lobby and on the 33rd floor. One man remains in critical condition in hospital.
