The jaws had no stability for its base nor at the lift point and just rolled over onto its side once the angle increased.
It’s a little hard to tell from the video, but the guys working the rescue tool might be police and not fire. That would more likely explain why the rescue tool was used in a way that would never, ever be taught in an accident victim extrication course. You can see a fire guy walking by with some step cribbing, but clearly the car fell before anything could be put under it.