This practice/path has to be very potent and elevated in order for even the very advanced to come to accept to simply step into the other side with no-fuss, given the preponderant identification with and, extremely desperate attachment to the physical body.
The traits of the practice are attractive and serious, that is my opinion. So much focus on death denotes a greatly advanced level of renunciation. And, perhaps at that point checking for vitals before incineration or incidental immolation might be easily and graciously overlooked?
Indeed, I’d say that this is akin to Lord Buddha and his true teachings! Although this extraordinary feat does not in and of itself does not give insight into the destination of such an exalted individual.