It is impossible to build a startup "inside" another company. If one understands what the word startup means. Therefore, the article's author does not.
i personally think "startup = new business and/or an effort to try creating a new viable business" is the best definition. otherwise they could say, well, they were doing new product R&D. no need to use the term startup. startups often have to find investors, find employees, etc. doing R&D for a new product within an existing and already profitable business is a different kind and magnitude of problem.