Maintaining situational awareness saved this rider's life.
Every rider knows to take extra care around trucks. Their blind spots are enormous, and their wind gusts can blow you all over the road. This particular rider was captured on video avoiding yet another truck-related hazard: turning into a pancake under the trailer as it rolled over onto its side.
Here we see a four-lane divided highway, somewhere in the world where you drive on the left instead of the right. The car with the camera begins to pass a large truck, then slows down around a tight curve. A motorcycle splits between them and takes its position ahead of the car and alongside the truck. The wisdom of this particular move is questionable, but from this point on, the rider does everything right.
As the curve tightens, the trailer begins to tip over, directly on top of the motorcycle. The rider reacts quickly, straightening up the bike and braking hard. This literally saves the rider's life, as the truck rolls over onto its right side precisely where the bike would have been had the rider not reacted quickly and properly.
There are two main things that the rider did well here. First was to maintain situational awareness. Instead of daydreaming or being sucked into music, the rider reacted almost immediately when the trailer began to tip. This gave the rider the extra time needed to get somewhere other than where the trailer was about to fall.
Secondly, despite being in the middle of a curve, the rider straightened out the bike before braking hard. Had the rider braked that hard while turning, they would've crashed, and since rubber tires slow you down better than metal, plastic, and leather, even the best reaction time would probably not have saved the rider from turning into a human pancake. By straightening out, the bike had the maximum traction available for braking. It needed and used all traction it had, not to mention all of the road, coming close to the center divider.
I'll give the rider additional credit for quickly checking the left lane, then moving past the crashed truck. After avoiding being squashed from above, it would be terrible if an inattentive driver squashed them from behind. Our camera car driver was quite attentive and gave the rider plenty of room, but the rider didn't assume that, and rightfully so. I may take away these points if the rider left the scene of the crash, which they might have. Another truck obscures the view around the curve, so it's hard to see if one of the scooters stopped on the side of the road is the one that narrowly escaped death here.
In any event, poor passing discipline aside, this is a great example of the MSF's acronym SEE: Search, Evaluate, Execute. The rider noticed something amiss with the truck because they were Searching and looking for hazards. Then they Evaluated the situation, realized they were about to become road pizza, and chose hard braking as the proper course of action. They Executed the maneuver well, straightening their line to maximize traction for braking. It wasn't the best quick-stop I've ever seen, but it was effective enough to avoid the crash, which is all that matters.
Source: Amazing Engineering