SAN JOSE (KPIX) – Newly released surveillance video by the Valley Transportation Authority shows the frantic moments both inside and outside the rail yard as a gunman opened fire during last month’s mass shooting in San Jose.

The video also shows the quick response by law enforcement that has been contributed to saving lives that day.

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“It was a little more personal for me, because I know some of the people that responded,” said retired San Jose Police Sgt. Fredrick Kotto. “When I watched the news, I saw my friends and I saw people I care about and my heart sinks. It was personal.”

The surveillance video captures a team of law enforcement from the Santa Clara County Sheriff’s Department as well as the San Jose Police Department responding just three minutes after Samuel Cassidy opens fire on his colleagues at the rail yard.

The video then shows a group of other law enforcement rushing to carry two victims to safety. It’s unclear if the victims survived in the video, but the group works to triage the victims.

The VTA also released radio traffic recordings among its employees that day, which showed how they used their radios to warn each other about the shooting. It also helped pinpoint where shots were heard and ultimately led law enforcement to Cassidy within minutes of arriving at the property.

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“Someone’s shooting right outside the door, upstairs,” someone can be heard saying in the recordings moments after at least two gunshots are also heard.

The cameras capture the first employees running for the door and away from the rail yard at 6:32 a.m. that Wednesday. Cassidy had set a timer to set his home on fire before he drove to his workplace that morning to carry out his plan.

“What we have right now is shots fired. Make sure your doors are closed,” an employee warns a train operator in the recordings.

Kotto said the radio communication that went on for several minutes as well as the actions of the employees who died protecting their colleagues are what prevented more casualties that day.

“Communication is key, because if we know where the suspect is or we know where we can isolate him or her that’ll be a great thing in saving lives,” said Kotto. “The amount of courage that the citizens showed, what they did, absolutely incredible. The initial thing to do is get away, is to run…if you can’t run, if you’re trapped, then hide. But if you’re going to hide, barricade the entrance to wherever you’re hiding because the shooter will try to open a door, and if it’s not easy they’ll move on because they’re looking for victims.”

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Nine VTA workers died that day. Cassidy was discovered with self-inflicted gunshot wounds. The motive for what is now known as the Bay Area’s deadliest mass shooting is still unknown.