Amazing what some people will do to try to solve a problem. Probably lost the key and took a destructive and relatively expensive approach. Drilling out the old lock cylinder is an easier and cheaper way to do it, new lock cylinders aren't that expensive. Maybe they felt they couldn't wait until a new lock arrived, but after drilling and removing the old cylinder a screwdriver would have worked until the new cylinder arrived. I'm not sure they could have removed the cylinder even after doing that.