It might seem amusing to see a man sauntering along a Formula One track, oblivious to the race cars hurtling around him.
But organisers, drivers and team officials were dead serious when they registered their concerns over the track invader's antics during Sunday's Singapore Airlines Singapore Grand Prix.
The 27-year-old man has since been arrested and is assisting police with investigations.
Closed-circuit television footage showed him clambering onto the track through an opening after Turn 13 of the race circuit on the Esplanade Bridge.
He then ambled across the track, before doubling up when he saw race leader Sebastian Vettel's Ferrari emerge from the turn. The incident prompted the deployment of the safety car.
OTHER F1 TRACK INVASIONS
2015 Chinese Grand Prix
A man ran across the main straight, narrowly missing a car before trying to enter Ferrari's garage. He reportedly asked to try a car but was handed over to security and arrested.
2003 British Grand Prix
A quilt-wearing priest got onto the track waving religious banners . He ran wildly at oncoming cars, causing drivers to swerve wildly to avoid him.
2000 German Grand Prix
A man walked on one side of the track before running across it as four cars sped towards him.
1989 Brazilian Grand Prix
Ferrari's Nigel Mansell was bearing down on the home straight when a man ran across the track.
A statement from the International Automobile Federation (FIA), F1's governing body, said: "We are awaiting a full report from the clerk of the course in order to determine the circumstances surrounding this incident."
A spokesman for race organisers Singapore GP said investigations are ongoing and a statement will be released soon.
Singapore racer Yuey Tan, who was watching the race from his hotel room after competing in the Porsche Carrera Cup Asia earlier on Sunday, said things could have easily spiralled out of control.
Said the 33-year-old: "If he (had entered the track) at a blind corner, he would have been smashed and killed. And with so many cars on the track going at speeds of 280kmh to 290kmh, so many other things could happen.
"Drivers could be hit by flying debris, or they could crash as they try to avoid each other as well as the man. It's important to figure out how it happened and make sure it doesn't occur again."
The Straits Times understands that, for the man to reach the track, he had to first scale a chest-high barricade to get to a 2m-wide corridor along the track where track marshals operate.
From there, he could then get on the track through an opening used by marshals to access the track to clear debris or other obstacles.
There are many such openings along the 5.065km Marina Bay Street Circuit, and these are usually manned by the marshals. There are also security personnel patrolling stretches of the track on foot.
A source said the culprit likely chose a time when both marshals and security officers were not looking. Track specifications, such as the barricade height, are guided by the FIA, the source added.
The incident caused widespread consternation among F1 drivers and officials. Manor president Graeme Lowdon told Autosport.com: "I'm sure it was a pretty scary thing for the drivers to come across, but the drivers managed the situation pretty well, and thankfully no one was hurt."
However, Tan believes it will not take the shine off the Singapore Grand Prix, which has been held since 2008. He said: "The important thing is to learn from this, educate the crowd on safety and tighten up security."