Jessica Chen was watching a presentation on the second floor of the number 345 Park Ave. in Midtown Manhattan on Monday night with about 150 people there when she said she heard multiple gunshots “in rapid succession” on the floor below. He ran into a conference room with dozens of others, where they eventually barricaded themselves inside using tables and “just stood still,” he told ABC News Live in a phone interview Monday. “I think it was very evident with all of this that a lot of us were young, a lot of us received training in elementary school on what to do in an active shooter situation,” he said. A man wearing body armor and carrying a high-powered rifle shot and killed at least four people, including a police officer outside on duty who worked as a security guard at the building, police sources told ABC News.

After apparently barricading himself on the 33rd floor, the suspect was found dead from what is believed to be a self-inflicted gunshot wound, the sources added. Amid the intense situation, people were frantically looking for somewhere to hide in the second-floor conference room, Chen said.

"We were hiding behind the large monitor. Many people were on the floor. We turned over a lot of tables," she said. "Some, if they came a little later, unfortunately, they had to draw the curtains to cover themselves."

Chen said someone in the room with her had a direct line to police, who were able to update them as the incident unfolded. She said many people were also on their phones, checking the news and contacting loved ones.

“I texted my parents and told them I loved them,” she said. “I texted the good people in my life and told them I loved them.”

She said those in the room tried to help each other stay as calm as possible. “Honestly, we were very, very scared,” he said.

“I think we all froze,” he continued. "We were all in shock. There's nothing that can describe that feeling."

Once they confirmed the shooter was on the 33rd floor, police ushered them out slowly and in an orderly fashion. He said he wasn't wearing shoes when he left and stepped on some glass, although he was otherwise fine.

"I think a lot of the people I've spoken to have come to the same conclusion: This happens way too often in America," Chen said. "We're really grateful to all the schools across the country that make sure they regularly train their students on what to do in situations like this."

"It's very unfortunate that all Americans have had to reflect on this, but it's the reality of the world we live in," he added.