The circular area where Cardenas had been is where the bloodshed finally ended with the gunman's shooting by law enforcement, according to the intelligence source. They didn't take any chances with the wounded suspect either, handcuffing him to a gurney as he was being carried out.
Actor Tim Daly said that when he was eventually led out of the the Virgin America first-class lounge, he saw where the incident came to a head around Gates 35 and 36. After being told not to step on any blood or glass, Daly spotted a high-powered rifle on the ground along with a pair of black shoes and several bags strewn across the floor.
Also there was more than 100 rounds of unspent ammunition, Los Angeles Mayor Eric Garcetti said, enough to "have literally killed everyone in that terminal today."
Los Angeles Police Chief Robert Beck credited the responding airport police officers with heroically saving lives with their efforts. It was a sentiment echoed by Mike Bonin, a city councilman whose district includes the airport and its surrounding neighborhoods.
"When shots rang out, members of the Los Angeles World Airport police department ran towards that gunfire, without regard to their own safety and well being," Bonin said. "... No doubt, without their efforts, the casualty count today would be significantly higher."
Hundreds of flights impacted
Even once the suspect was shot and detained, law enforcement officers roamed the airport with guns drawn looking for others who might have involved.
KCAL showed live video of three officers with rifles to their shoulders inspecting parked cars in an open-air parking lot. At one point, firefighters lay tarps on the street at the airport, apparently for triage.
The episode soon rendered one of the world's busiest airports a ghost town. Large portions were evacuated as authorities ordered a "ground stop" for arriving planes that lasted four hours.
About 750 flights were affected by the ordeal, including 46 would-be arriving aircraft that were diverted to other nearby airports, said Gina Marie Lindsay, executive director of Los Angeles World Airports. Some that did touch down were held on the ground in Los Angeles, while others didn't leave their originating airports.
LAX, as it's known, was a mess.
The area around the airport was jammed with cars as police shut down access. Meanwhile, many who were in the terminals, waiting for flights to arrive or depart, were pushed out.
Even as late as 4 p.m. -- some 6½ hours after the shooting occurred -- masses were still huddled on sidewalks outside the airport, because they had no place else to go.
Soon after that, people started moving back in as the airport operations kicked back into gear. Terminal 3, though, remained closed -- all flights that were supposed to go in and out of there were relocated elsewhere in the airport -- and will be "for a while," said Bowdich of the FBI.
"This has been a trying day for everyone, I know," Lindsay said.
That's especially true for members of the TSA, which lost one of its own Friday and had two others wounded.
The federal agency's chief, John Pistole, is heading to Los Angeles on Saturday. Before he left, he sent a message to his employees thanking them for their good work and support for each other.
"Together, we will get through this," Pistole wrote. "Our faith will guide us and our professionalism will ensure our ability to carry out our mission."