Thank you, I lost my mind, briefly, reading that part.

Light slows down in dielectric materials because as an em wave it interacts with the polarization of molecules. Neutrino has very little interaction with matter, OTOH.

This is also the source of the classic blue glow in water cooled nuclear reactors. Electrons move through the water faster than light and leave behind a kind of 'sonic boom' of photons in its wake.