The woman, known only by her account name of herrydrk, shared photos of a pile of chairs and a bin against a door in the Bronx Lebanon Hospital in the city.
She is believed to have blocked herself inside the toilet as former doctor Henry Bello ran amok in the hospital, shooting a former colleague dead before taking his own life.
The woman posted another photo of herself in the mirror, which was originally captioned: "Nice start of the weekend."Related articles
INSTAGRAMThe woman posted a selfie of herself with the barricade
I am grateful to be alive
Instagram user herrydrk
But as the true horror of the incident unfolded, the caption was changed to: “Stayed safe during the crisis.”
Another post went into detail about the ordeal an hour after Bello turned his weapon on himself.