It would be the most or highest terrible painful suffering of the total amount of not only the accumulation of all kinds of countless painful suffering that all and everyone are having in this present selfless impermanent life existence now, but also the accumulation of all kinds of countless painful suffering that all life forms had had in the countless life existence in the past, ever since the beginning of selfless impermanent mortal existence of countless life forms or names and forms in this world of ignorance and consequences of ignorance, if the selfless silent witness is not selfless, but is having an immortal individual existence that is ever existing in here and everywhere since infinite ancient time even long before the beginning of the universe, that is limitless beyond time, space and causation, while witnessing all those suffering infinitely under an immortal individual existence, of 'I' am existing and witnessing all these painful suffering of many others, without an end.
Similarly, why would anyone, or more precisely, any thinking mind, if under certain degrees of clarity of thinking and correct understanding, would desire to be 'something' immortal that exists forever, either to attain immortality, or to regain immortality, if that is what all and everyone originally is, according to the many existing cultural, spiritual or religious beliefs in the world of limited and conditional selfless impermanent names and forms, where all are existing impermanently here, while waiting to regain their immortality of an 'immortal individual infinite existence' that has been existing infinitely, where all 'immortal individual infinite existence' have been infinitely witnessing all kinds of selfless impermanent names and forms arising, changing, and passing away, of all kinds of countless physical, mental and emotional suffering of ignorance and the consequences of ignorance in the world, due to countless 'immortal individual infinite existence' have been being born and reborn ceaselessly into the world of impermanence and mortality to be suffering all kinds of limited conditional selfless impermanent changes due to an 'ignorant downfall' or 'sin'?
If there will be 'ignorant downfall' in all these countless 'immortal individual infinite existence' to be born into 'impermanent mortal existence' to be suffering from ceaseless impermanent births and deaths governed by the inexhaustible 'karma' from then on, that means, they are not unconditional, and there are still limitation, in such 'immortal individual infinite existence'.
And if, all and everyone and everything exist infinitely in the world, where there's no selfless impermanent changes of decay, aging and disintegration in all and everything, while many more 'immortal individual infinite existence' that is unborn, but merely appearing in the world from no where, and then would just keep existing infinitely, just like all the other 'immortal individual infinite existence' that were unborn, but somehow they just appear in the universe coming from no where, if so, imagine what a 'chaos' and 'congested' world and universe it can be, where there are countless immortal individual infinite existence that keep appearing as they are coming from no where, without a cause and unborn, where all and everyone manifest all and everything under their boundless desire limitlessly.
That's why the truth of selflessness and impermanence in all kinds of names and forms, where all and everything is subject to be arising, changing, and passing away under the nature's law of cause and effect, that is limited and conditional, that has a beginning and an ending, is no doubt a form of inevitable suffering for many selfless minds under the veil of ignorance and egoism, but at the same time it is absolutely liberating.
That is also why the teachings of yoga and buddhism is about attaining silence and desirelessness, and not about attaining or regaining immortality of having an 'infinite individual existence' without impermanent changes, without an end, to be having unlimited superpower of manifesting all and everything exactly the way that how all the different countless 'I' or 'infinite individual existence' would like it to be, to be accomplishing all their boundless individual desires limitlessly, to be enjoying unlimited pleasurable desirable enjoyments. If that is possible, if that is happening, imagine what the universe will be like, complete madness.
And the selfless impure restless modification of the many selfless minds that are lost in ignorance and egoism in this world, in this present moment, are not any different from this madness, occupying by boundless desires and wild imaginations, on top of materializing all their thoughts, desires, actions and reactions into the surrounding environment through the selfless organs of actions and speech of the selfless physical body, generating all kinds of damaging effects and disturbance unto oneself and all and everything to the maximum.
Inquire towards the truth of everything.