"Listening to some of the radio traffic that was going on (Sunday night), that team was very composed and calm," said Sgt. Ray Kelly of the Alameda County Sheriff's Office, which organizes the annual training program.
Kelly showed us one of the armored vehicles used for the training, which includes using explosives to break down a door -- one way to catch an active shooter off guard. He added that, while armored vehicles can bring officers into a dangerous situation, they can also be used to transport injured patients to safety.
"It's times like these that we realize that our first responders need to be well trained," he said.
Urban Shield has drawn criticism from protesters who demonstrate in front of the event nearly every time it's held.
"When police arm themselves with military grade weaponry, what we're going to see is more violence," said Mohamed Shehk of the Stop Urban Shield Coalition.
He said armor and big guns can serve to deepen the divide between the people and the police -- especially in poor neighborhoods or communities of color, when SWAT teams are sometimes called upon to serve search warrants and may show up with the same gear they'd use to subdue an active shooter.
"We feel these lead to a complete breakdown of any kind of trust that exists with the community and the police," he said.
The Alameda County Sheriff's Office says its heavily armored tactical vehicles are for defensive purposes only -- intended to protect officers as they approach a dangerous situation with an unknown threat.
"Every year, we see a change in tactics by the bad guys out there," Kelly said.
He added that next year's Urban Shield training will likely include a scenario similar to the one in Las Vegas: "How do you prevent high rise, high density attacks on innocent people?"