The feeling of being dead in a vision or dream experience comes when something in the being is to be silenced into entire inactivity and ceases to exist as part of the nature. It may be a very small part, but as during the process the consciousness is concentrated in it and identified with it for the purpose of the working, the feeling is that "I am dead."
To merge the consciousness in the Divine and to keep the psychic being controlling and changing all the nature and keeping it turned to the Divine till the whole being can live in the Divine is the transformation we seek. There is further the supramentalisation, but this only carries the transformation to its own highest and largest possibilities — it does not alter its essential nature.
Immortality is one of the possible results of supramentalisation, but it is not an obligatory result and it does not mean that there will be an eternal or indefinite prolongation of life as it is. That is what many think it will be, that they will remain what they are with all their human desires and the only difference will be that they will satisfy them endlessly; but such an immortality would not be worth having and it would not be long before people are tired of it. To live in the Divine and have the divine Consciousness is itself immortality and to be able to divinise the body also and make it a fit instrument for divine works and divine life would be its material expression only.
As the height draws the low ever to climb,
As the breadths draw the small to adventure vast,
Their aloofness drives man to surpass himself.
Our passion heaves to wed the eternal calm,
Our dwarf-search mind to meet the Omniscient's force.