It's a stress test. You would expect things to break during a stress test.
> "They loaded it up well beyond capacity and bent its wings in an extreme manner, in a way almost certain to never happen in the real world."
Here is another video of a 777 wing test where it broke at 154% of the [s/normal/maximum theoretical/] load - a bit beyond what was expected by the engineering team. https://www.youtube.com/watch?v=Ai2HmvAXcU0
> "They loaded it up well beyond capacity and bent its wings in an extreme manner, in a way almost certain to never happen in the real world."
Here is another video of a 777 wing test where it broke at 154% of the [s/normal/maximum theoretical/] load - a bit beyond what was expected by the engineering team. https://www.youtube.com/watch?v=Ai2HmvAXcU0