Heroic Uber driver drives YouTube employees to safety during shooting

SAN BRUNO, Calif. -- Police say the women who shot three people before turning the gun on herself Tuesday legally purchased the gun in San Diego in January. The nine-millimeter Smith and Wesson was registered in Nasim Aghdam's name.

Officials at Zuckerberg San Francisco General Hospital on Thursday said the most seriously injured victim of the shooting is improving. The 36-year-old man has been upgraded to fair condition. The two women wounded in the shooting have been released.

TIMELINE: Nasim Aghdam's movements leading up to YouTube HQ shooting

There have been new stories of heroism from Tuesday's attack.

The momentary scare for YouTube employees happened when a fire alarm was pulled and firefighters responded Thursday morning. They didn't know if it was intentional, but it did nothing to calm the nerves of employees returning to work for the first time since the shooting Tuesday.

San Bruno Police say security at the campus has been increased. Security guards were posted at all entrances and a police car appeared out front.

Police say Aghdam's shooting rampage lasted three minutes. In the middle of it, she reloaded her gun.

RELATED: YouTube shooting suspect's family in Menifee says they warned police ahead of attack

"During the incident she exchanged the magazine and continued firing," said Commander Geoff Caldwell of the San Bruno Police.

Officials add that Aghdam bought the nine-millimeter pistol from a gun dealer in San Diego in January.

"For all intent and purpose, she bought the gun legally," said Caldwell.

Aghdam took her own life.

RELATED: Police say YouTube shooting suspect's family gave no warning of potential violence

"I think people need help, you know," said San Bruno Uber driver Lucasio Simoes. Moments after the shooting a friend told him to stay away from the scene, but Simoes drove his Ford Explorer toward YouTube. "I turned off the app and gave people a ride. We didn't know who was the shooter."

Simoes doesn't remember how many YouTube employees he helped, but made at least eight trips to and from Tanforan Mall.

"It's sad. Everyone was shaking, crying. I wanted to let them know everything was okay," said Simoes.

Click here for full coverage on the YouTube shooting in San Bruno.