A woman who was right next to the victim ofsays it was "kind of surreal" and she "couldn't believe it was happening."
Maria Coste-Weber told CBS New York she witnessed a nightmare unfold right in front of her in a split second.
The Manhattan resident was in the Times Square station Saturday morning when she noticed a commotion near her.
"As I looked to the left, I see this man start charging towards the tracks, like, with his hands in front of him," she said.
Coste-Weber then watched in horror as the man pushed a woman identified by authorities as 40-year-old Michelle Alyssa Go from behind and right into the path of an oncoming train.
"Just seconds. The train passed. The impact and … she went in front of it, and then you saw her disappear from the tracks," Coste-Weber recalled.
Coste-Weber says what happened next is a blur. She and others scrambled for help.
"We all kind of got in shock and everybody started running up the stairs and stuff like that," she said. "Yeah, it was pretty hard."
Go, an Upper West Side resident, died at the scene.
Authorities have charged Simon Martial, 61, with second-degree murder.
Police say he's homeless and has a previous record of three emotionally disturbed incidents. Sources tell CBS New York Martial has four prior arrests and has spent time in prison.
Police say before the fatal push, Martial also taunted another woman on the subway platform, but she managed to escape unharmed.
Coste-Weber wants to see more resources for those with mental illness in the system, along with more officers. For now, she's grateful to be alive.
"That could have been me there because I was right next to her," she said. "I feel sad for her, you know, her family. I feel so sad for them."
According to Go's LinkedIn account, she was a consultant at Deloitte Touche Tohmatsu Limited, commonly referred to simply as Deloitte, and an avid volunteer.
The New York Junior League says Go worked with the organization's community partners, serving under-resourced and at-risk communities. Go served on a committee for a preventative health education initiative and another committee with the goal of empowering adults on the path to independent success.
Those who worked with Go called her "compassionate" and "instrumental" to their work.
At the building where she lived, neighbors described her as smart, intelligent and extremely kind.