I've seen and commented on this vid or one like it before, This is what happens when you pause or stall a leaner, he should have kept cutting without stopping, its the pause that allowed it to stall and build all that pressure on the hinge, if he had kept cutting the pressure would have released itself through a smaller hinge wood and gravity would have taken over.
Also dude needs a bigger saw if he wants to mess around with leaners, and conventional cutting methods, more power = faster cutting, the alternative is to waste all day using the GOL cut or Swedish stump dance