India, July 31 -- Julia Hyman had reached the safety of a fortified panic room inside her office at 345 Park Ave. during the Midtown mass shooting. But when she briefly stepped out, gunman Shane Tamura fatally shot her, according to a chilling new timeline of the rampage.

As Tamura stepped out of the elevator and started firing an assault fire, the 27-year-old employee of Rudin Management rushed to the panic room on Monday evening. The panic room was hidden in the bathroom located on the 33rd floor, officials familiar with the investigation told The Post.

According to the officials, the panic room was equipped with a ballistic door, locking bolts, a hard-wired phone, and even a live camera feed, which looked into the hall.

Meanwhile, T...