For context how how this applies to you, below gives further elucidation how one can never negate self; the conscious-subject. “I” can't go out of existence. Inquiry begins:
If we look into names/forms (nāma-rūpa) including time and space, we can keep reducing them to mere thought/concept level.
However even thought can be reduced.
For instance, is there concept of time when not concerned of time? Is there time amidst deep meditation or throughout immersive hobby/sport? No. Sense of ongoing progression disappears. But remains what? The conscious-subject.
In this way, we observe conscious-subject can't be reduced further. I can't reduce myself. Even if I did, then who would be left to validate the absence of self, the conscious-subject?
That is to say, Conscious “I” never goes out of existence. If we analyze our life, we find I was never NOT available. Even if there as no experience of anything, “I” was still present illuminating the experience of nothing-in-particular.
What about deep sleep? I am NOT available there!
If you asked above question, you've contradicted yourself.
How can “I” ask about an experience to which it wasn't available to? Impossible.
“I” always asks about an event to which the “I” was a witness to.
Point is you're asking about “deep sleep” because “I” is also available then. It's true that mind is not available, which is why we have nothing to say about deep sleep, except a generic label “deep sleep”. Then we try to define it vaguely as: nothing, void, darkness, blackness, non-existence, absence, bliss, happiness, freedom, rest.
The point is – to describe deep sleep with any of those definitions, it's only possible if “I” was present throughout deep sleep.
In short: It's impossible to negate one's awareness/consciousness. Else who'd be left to say “I negated myself”. Who would be observing the glories dissolution of the conscious-subject going out of existence?
Even if one says God, then how does one know that “God was observing”? That implies “I was available to observe God observing”.
Meaning the entire universe of objects, ultimately is reduced to conscious-subject, self. And conscious-subject can't be further reduced.
Therefore the conscious-subject is Limitlessness because it is not bound by LIMITED thoughts, forms, nor time-space.