You might say that he tried to be discreet but then blew it again, as he posted the video online for everyone to see. The French sedan's systems managed to keep the vehicle centered within the lane for a while.
Unfortunately, things went South because of unclear lane markings, and then the amateur cameraman's troubles began after the system stopped attempting to maintain the vehicle between the white lines that limit the lane.
The vehicle then veered off the road, and the other person, sitting in the passenger's seat, attempted to prevent a crash by intervening with his hands. Unfortunately, his intervention was too hasty or included too many corrections, and the vehicle then left the highway. As a local rally driver pointed out in the comments section, the water bottle fell asleep behind the wheel.
Fortunately for everyone else on the road, the pair did not hit another vehicle when it crashed. Moreover, while the two men will probably be in legal trouble after their video goes viral, they appear to be uninjured, which makes the video funny.
It should also serve as a warning to all who attempt to trick these lane assist systems. This technology is designed to help the driver maintain the lane while using cruise control and make journeys more relaxing.
The systems of the vehicle have no blame here, as the driver is the only one responsible for what happens to a car while it is being operated on the road. Do not try to replicate what you have seen in this video, as you risk crashing your vehicle and injuring yourself and others.