There's nothing that Bill Hammer could have done to prepare him for the night of June 12, 2016.

"You don't know what happens," he said. "You don't know if they made it through it."

Hammer is one of the many 911 caller operators who manned the lines during the night of the attack on Pulse, the gay Orlando nightclub.

"It's basically a narrative, a storyline for the officer to know what he's getting himself into," he said. "My first step, depending on their demeanor, is to calm them down to a level where I can get an understanding. Tactics of, 'Take a deep breath; I'm here for you.' "

For the past seven years, Hammer has been answering calls from a center along George Desalvia Way. But at about 2:03 a.m. June 12, 2016, he took a call only seconds long. It was punctuated by gunshots.

"It was a male," Hammer recalled. "I could tell he was breathing very heavily. That phone disconnected."

Hammer was almost at the end of a 12-hour shift. Instead, it was just the beginning of what would be a very long day.

Throughout the early morning hours, Hammer spoke to several victims, including a man shot in the stomach who was hiding in a small office above the club's kitchen.

"He said there were six people in the office of the kitchen upstairs, and you have to climb a small ladder to get up there," Hammer said of the 911 call.

Hammer guided SWAT officers to the group, instructing them to exit the room with their hands up.

It was a phone call the operator took later in the morning that shook him to his core.

A woman called from her hiding space with several other victims inside a dressing room. They would be the second-to-last group to be rescued from the club.

"I said, 'Calm down; I'm on the phone with you. I'm going to stay on the phone with you,'" Hammer recalled. "When they came to give me relief, I just refused. I was not going to get up from that chair, because I promised that young girl who I'm on the phone with that I'm not leaving her."

The conversation lasted more than 90 minutes. Bonds were forged over light moments of the stressful and frightening situation, such as when Hammer asked whether she had children.

"Uh, no. I have a full life ahead of me," the woman told Hammer.

"You're going to have a story to tell (them) one day, huh?" Hammer replied.

"I hope. I really hope so," she said.

Over time, the conversation — Hammer keeping the woman calm in order to calm others in the room — turned to escape as the group spotted an air-conditioning unit in the window. The woman said she thought the group might be able to push out the unit and escape through the hole.

One by one, they climbed out the window. The woman and Hammer stayed on the line.

"She said, 'I will be the last person to go out this window.' And she was," he said.

Then came the familiar silence. Hammer could be heard on the 911 call wondering aloud whether the woman he spoke to for so long got out safely.

That silence following a call is something Hammer has gotten used to, though it doesn't make it any easier.

"I can write a 100-chapter book about calls I've taken, but I can never finish the chapter," he said. "Every call we take, there is an emotional connection, only because we don't know the ending. And that's the hardest part of the job."

For Hammer, that last call still plagues him.

"If ever there was a chance I could give her a big hug... Because, to me, she was the hero that night," he said. "I'll remember her probably the rest of my life."