But you're not dead? Nobody alive is! Can we rule out personal exp?
Yes we can drop that part of it and I can bring what I've learned in physics and medicine. The rushing sound is what we refer to as a modified Divers reflex. As the peripheral vasculature shuts down, in a modification left over from birth, we funnel all our blood supply to our central organs. The last to get deprived is the heart but just before that is the brain. That rushing sound is our vasculature making it's last ditch attempt at keeping the brain perfused. In neurosurgery we correlated this with changes in the EEG and EKG and the support devices available to us.
Because our brains schematize we usually translate this rushing as language especially as we age and the flow is no longer in a completely clean pipe. So that is what explains the buzzing.
Next the branes; energy and data can cross, our physics know this, but matter can not. We can't take corporeal existence with us. But all energy and data remains and goes forward.
In other words from everything I've learned over a lifetime of science and mathematics I have to say my experience matches. But you are right anecdotal experience means almost nothing. But look into the work of Raymond Moody. Look at his book about shared death experience; Glimpses of Eternity. All the 'paranormal' experiences in current literature. Essentially we simply do not know how to look objectively/scientifically at the rest of our 'natural' world. But one day physics will explain how ghosts et. al. are real etc.... We simply don't have the full physics book yet. We are still in the topology phase. But we keep getting closer when we work in a scientific manner to attempt to describe the limits of our domain.
Especially those uncomfortable and more speculative areas that science has disowned because of lack of ability to easily objectively test and shameful territoriality on the part of our white coat boys, the Ph.D. who guard the gates of what is 'real' science.
When every mathematician knows it only gets interesting at the edges of the domain. That's where you focus