It was just a drill.
Sacramento Police SWAT teams do table top exercises once a week, but these live drills are a little less frequent and much more elaborate.
"It's really a sense of controlled chaos," said Sacramento Police Lieutenant Bryce Heinlein.
Wednesday morning's drill was a person inside the Sawyer Hotel, which overlooks the Golden 1 Center, shooting down into a group of people. SWAT, first responders and security officers ran around the arena.
"It was simulated to be as realistic as possible. So there were amplified sounds of gunfire, screaming, getting role players to do certain activities to throw the officers off, so there are a lot of distractions that are going on," Heinlein said.
With the mass shooting in Las Vegas still fresh on everyone's minds, officers and security teams take these drills seriously.
"We also need to learn from these types of incidents that occur in the nation, and continue to train at a high level," Heinlein told FOX40. "Identifying a threat, going towards that threat, and isolating it."