Is there such a thing as unsafe cpu levels on mac? Background: The process com.docker.hyperkit has consistently been using between 100% and 200% cpu on my mac (which has 2 physical, and (in total) 4 virtual cores). 

Question: is there such a thing as unsafe CPU levels (as displayed in the activity monitor) on a mac? If so, at what levels should I get worried?
No. Your CPU will thermally throttle itself if it becomes too hot.  If it goes beyond its thermal limit, it will shut itself off. 

The only thing you actually have to worry about is reduced performance.