The reigning Formula One world champion was returning from the Interlagos track on the outskirts of Sao Paulo, where he had just qualified for the Brazilian Grand Prix.
But it was the driving skills of Daniel Toni, a policeman on secondment to the McLaren team, that saved Button as he smashed his way through heavy traffic in a scene that resembled an action movie.
Security was stepped up around the circuit before the start of the grand prix, but the attack on such a high-profile personality is intensely damaging to the Brazilian government which is preparing to host the 2014 football World Cup and the Olympic Games two years later.
In separate incidents at about the same time, a group of team mechanics and a motor racing executive were robbed at gunpoint.
Button, who finished fifth in Sunday's Grand Prix, was travelling with John, his father, Richard Goddard, his manager, and Mike Collier, his trainer, on Saturday night when their armoured Mercedes B-Class pulled up at traffic lights on the three-lane highway that runs alongside the notorious favelas - shanty towns that are home to millions of the poorest people in Brazil.
Six men emerged from a shadowy doorway and headed for Button's car.
"We were three rows back," Button said. "Our driver always stops early and doesn't pull up right behind the car in front. We saw a few guys gathering on the side of the road. They looked a bit suspect but we didn't think anything of it. Then I noticed one guy was playing around with something in his trousers and it was a gun."
As the gunmen ran to the car, Button screamed at his driver: "F*** me, he has got a gun. Go, go, go." Mr Toni, an officer with elite protection training, who has chauffeured celebrities such as Madonna, put his foot down and smashed into the two cars ahead of him.
Within seconds, the Mercedes was tearing between traffic, scraping its bodywork and leaving behind a line of damaged cars.
"He just rammed every single car to get past," Button said.
"We got through in the end but, as we were crashing along, we looked back and there were two guys with handguns and one with what looked like a machinegun. Initially you think it is random. Afterwards, all sorts of things go through your mind. I am hoping we were just unlucky."
Seven mechanics from the BMW Sauber team were stopped in their minibus and robbed of their valuables at gunpoint. An unnamed team executive was also robbed outside his hotel.
