Hiding with his terrified colleagues beneath a table while a masked gunman sprayed bullets through the San Bernardino conference room, Corwin Porter refused at first to believe what he was seeing.
"I think we, in in the back of our mind, were hoping that it was an exercise that someone tried to spring, to test our readiness," he said. We were "resisting believing it could actually be a real event."
But it was all too real. And in an interview Monday with NBC News, Porter and another survivor of last week's slaughter that killed 14 of their co-workers recounted their hellish brush with death.
Speaking in the flat tones of people who have seen too much, Porter and Trudy Raymundo, his boss at the San Bernardino County Department of Public Health, said they had been at the Inland Regional Center for about an hour when the shooting started.
"I heard some pop, pop, pop sounds that sounded like fireworks going off," he said. "I was trying to believe it might be firecrackers and someone just was, you know, playing a joke."
Raymundo said she was grabbing a cup of coffee when she heard the noise.
Then, she said, "the doors flew open, the gunman came in."
Police said county worker Syed Farook and his wife, Tafsheen Malik, barged inside and began firing. Porter and Raymundo said they only saw one shooter.
"He was walking towards the middle of the room," Raymundo said. "It was all very fast."
Asked what they did next, Raymundo looked over at Porter and then said, "We dropped."
"I just remember the gunfire starting almost immediately," Porter said. "Almost immediately as soon as that door opened it seemed like gunfire just started."
Porter said the shooter did not appear to be firing at anybody in particular.
"It looked to me like (he was) spraying the room," he said. "But in the area where the staff was congregating."
Raymundo and Porter said there was no yelling or screaming — just shooting.
"My thoughts were ... is this really an exercise and how can I get control of the situation," Porter said.
"For me it was just, 'Why doesn't he stop? Why doesn't he stop? Why won't he stop shooting," Raymundo said.
"Out of desperation," Raymundo added, she too began hoping this was all an act and that all her dead co-workers were just pretending to be dead.
"Hoping the people in front of you are fine, fine and are going to get up," she said.
There were three exits in the conference room, but nobody tried to escape, they said.
"To stand up and go for the doors, you're in the line of sight of the gunman," Porter said. "We were under the tables ourselves, doing what we were trained to do."
Raymundo said they were "trying to stay as quiet as possible."
"We didn't want them to know where we were," she said.
Raymundo said they stayed put after the shooting stopped and "the police came in."
After that, she said, "we assisted who we could that was injured."
While there have been reports that Farook got into an argument with someone at the gathering and then left to fetch his wife and their guns, both Porter and Raymundo said they saw no sign of that and said everybody seemed to be "upbeat."
The FBI now suspects the Chicago-born Farook and his Pakistani bride were waging jihad when they shot-up the conference room. Another 21 people were wounded.
"I don't know that there is an answer to that," Porter said, when asked why the couple massacred their friends.
Asked if they felt guilty that they survived without a scratch, Raymundo and Porter looked at each other again before saying yes.
"When you're the one surviving, when you're the one left behind, it's incredibly difficult," Raymundo said.
"It's hard," Porter chimed-in, looking for a brief moment like he might cry."These were our friends. These were our family."