Mole I totally agree , in your case living underground it shouldn’t be an issue but for all crews it most certainly is
Cosmic radiation has been an issue since the advent of the jet age , only now is it coming to light . Look at the
http://jag.cami.jccbi.gov/cariprofile.asp website insert a flight say from JFK - HKG using the normal levels we cruise at , then do the same flight but at 4000ft lower and see the difference in radiation levels it’s staggering . Sadly for most of the people I fly with it’s a case of ignorance is bliss let’s climb to FL 410 thanks but no thanks
Or if you prefer.
https://www.omnicalculator.com/other/flight-radiation