The rocket was undergoing a static fire test of the stage, in which a vehicle is clamped to a test stand while its engines are ignited, when the booster broke free. According to a statement from the company, the rocket was not sufficiently clamped down and blasted off from the test stand “due to a structural failure.”
Video of the accidental ascent showed the rocket rising several hundred meters into the sky before it crashed explosively into a mountain 1.5 km away from the test site.
Real life Kerbal Space Program accident.
Except the test facility was dangerously close to city resulting at minimum in an enormous amount of broken windows (clearly heard in the recorded videos) and no doubt damage to people associated with large volumes of windows breaking.