Tragically, Walker had been getting ready to leave his Reach Out Worldwide charity event on Saturday and had already said most of his goodbyes when he and Rodas decided to take the 2005 Porsche Carrera GT that they ultimately died in out for a test drive.
The Porsche had been stalling and Rodas suggested that they go for a drive to try to diagnose the problem, and Walker agreed, a source who witnessed the exchange exclusively told E! News Monday.
"I've seen both Paul and Roger drive on the race track," the source said. "These guys are good drivers. They are responsible drivers."
The pair wanting to take the sports car for a spin seemed perfectly normal, the witness added, saying, "That's typical of any car shop. If it has an issue, people will take it out and see what's wrong with it."
Walker was "smiling and happy," the source recalled. The 40-year-old actor then jumped in the car, fastened his seat belt and "said something like, 'be right back.'"
As for suggestions that drag racing was involved, the area in which the crash occurred said to be a popular spot for street racing, the source reiterated that the guys were "responsible" and he found it hard to fathom that Walker and Rodas had decided to "do 100 on a side street" just for a joyride.
They were gone "maybe five minutes...they had just taken off," the source continued, when a blue BMW M3 came screeching into the parking lot and the driver shouted, "'There's been a crash, somebody come help!'"
"Some people from the event jumped in the car and drove up there. Some guys grabbed fire extinguishers, and went there, that's when they realized it was Paul and Roger. The fire department had already been called...It was bad, it was not something people should have to see."
The Porsche had slammed into a light pole and burst into flames near Hercules Street at Kelly Johnson Parkway in Santa Clarita, Calif.
A spokesman for the L.A. County Coroner Department confirmed earlier today that remains have still not been officially identified, but autopsies are tentatively scheduled for Tuesday.
"I just remember seeing the car, pretty much split in half, and there was debris in the other parking lot," the source told us. "The building right next to where they crashed, it has a glass space in front of the building. A piece of the car hit the building, and it shattered at the top, it had some force.
"That car isn't metal, that car is almost all carbon fiber. The body is all carbon fiber, it's very lightweight. It's such a rare collector car, but it's also a very dangerous car."
A spokesperson for the L.A. County Sheriff's Department told E! News today that traffic investigators from the Santa Clarita Valley Sheriff's Station have heard from witnesses that the Porsche seemed to be traveling at a high rate of speed before the crash. No one has contacted authorities about a possible second vehicle being involved.
Our source said that he had overheard one of the event employees trying to back the Porsche up into the garage where the other vehicles that had been on display were being parked after the event had ended, and the car stalled out on him.
The tragedy followed what had been a triumphant day for Reach Out Worldwide, the charity Walker set up after the earthquake in Haiti to benefit victims of natural disasters.
"People came to the event, and they had a hood of a car open with no engine, so they filled it all with toys," our source said. The empty car ultimately couldn't contain the donations, and many people donated bicycles, so they had to move the overflowing toy drive inside.
—Additional reporting by Holly Passalaqua