Is there even such a thing as “private firefighters“? 
Discussion
There is. They're mostly employed by insurance companies that insure wealthy homeowners and property management groups.
https://www.ziprecruiter.com/career/Private-Firefighter/What-Is-How-to-Become
Interesting.
If you're insuring multi-million dollar properties, I suppose it does make some sense to pay for a private firefighting force that can respond extremely fast with the best equipment. Even if a call-out costs you $100k, it's better than having to pay out the full value of the home.
All of this reminds me of a series of unfortunate events.