This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

Los Angeles firefighter Andrew Tom hadn’t been inside the downtown building long when he heard the boom.

Other firefighters said it was like a jet engine rocketing to life. Tom just knew it meant something terrible was about to happen.

Seconds later, as flames consumed the room and lapped at his LAFD gear, Tom thought about his fire academy training and what he’d been told about a “flash over” — the amount of time that combustible materials will take to ignite during an enclosed fire.

“They always say five seconds, or you’re gonna die. Five seconds went by. Ten seconds went by … I was like there’s no way I’m getting out, at all,” Tom said. “That’s where my mind went into: It’s over. I’m gonna die in here.”

Read the full story on LATimes.com.