The active-shooter drill was held in a wing adjacent to the old Nordstrom building on the west side of the shopping center.
Deputies from the Los Angeles County Sheriff's Department took part in three different scenarios. They faced gunfire, pipe bombs and dozens of victims with fake injuries. Officials say the emergency training was meant to catch law enforcement officers by surprise just as they would if there was a real shooter in the mall.
"They put different scenarios on so that the deputies are not exactly prepared on what to do, but at the same time in a real-life scenario, you're not prepared either, so it's about the preparation," sheriff's Capt. Keith Swensson.
SWAT officers repelled from a helicopter into the shopping center's parking lot. At an entrance, deputies walked in with guns drawn.
"Every inch of your muscle is intense, but you got to just realize and go with your training, and you got to face the suspect," said Deputy Luke Liu.
Tuesday's drill included deputies from Cerritos, Lakewood, Norwalk and Pico Rivera. L.A. County firefighters, mall security personnel and store employees also participated.
The drill was planned well before the shooting at LAX and at the Garden State Plaza mall in Paramus, N.J. Participants felt this drill hit home.
"Adrenaline goes up and my mindset is just this is for real; this isn't just training because who knows? It might happen here one day," said Deputy Leticia Reynoso.
Sheriff's officials say drills like this one are essential. Similar drills have been conducted in different places all over Southern California. Back in August, there was a drill at the Victoria Gardens Shopping Center in Rancho Cucamonga. In that situation, police officers and firefighters worked together and simulated a gunman opening fire inside a movie theater.