1. Philosophers and AI theoreticians have a hard time defining what they mean by the term "intelligence". Talking about systems millions of times more intelligent than a human is nonsense unless you can define what it is you're talking about.
2. Whatever intelligence is it only makes any sense within the context of some environment. Environments impose a multitude of constraints. In the "intelligence explosion" scenario the environment is assumed to be constraint free, or something close to it.
3. Be wary of people trying to sell you ideas based on fear. It's usually snake oil, concealing some other agenda - such as trying to obtain or maintain grant money for projects.
4. That many top AI people have "bug out" houses is simply false. An exaggeration, intended to add drama to the article.
5. Historically, the predictions of top AI researchers have not proven to be particularly accurate, although that does not mean that this will always be the case.