‘Sva’ means ‘in oneself that is to say ‘in Brahman’. ‘Apyayat’ means ‘since it merges’. The two words convey this meaning. They tell us, ‘since it is said that the individual Jiva merges in Brahman’, what happens to the Jiva during dreamless sleep is its resumption of its real nature, Sat or Being. Since the self attains the Self, which is Itself, it is then the Atma and nothing else. The Atma, which appeared as if enclosed in name and form discards the name and form and merges in the Universal Atma. The wave has merged in the dream. It had Become; now it is just Being, Sat.
The core of all Vedantic texts and teachings is this truth: (1) Brahman is both the efficient and material cause of the Jagat, the cosmos, which merges and emerges (Ja and Ga) and (2) Brahman is one and one only and so there is nothing in the cosmos apart from Brahman, without consciousness. There is nothing jada or inert and inactive. Brahman is, according to the scriptures (Sruti) and Vedanta texts, not only Sat but also Cit, Consciousness, awareness. During dreamless sleep, the Jiva enters and revels in the Anandaloka, the region of Bliss, led thereto by the splendour of the Udana prana, the vital air that elevates. That region is known also as Brahma Loka, the ananda Loka. This is the splendid chance that man gets effortless by during sleep, the chance to enjoy the proximity of the Parma - Atma which is the prime source and substance of the five Basic Elements, the five senses and the Inner Instrument of Awareness - the Five Bhutas, the Five Indriyas and the Antahkarana.
But this experience doesn’t last; it is quite temporary. The person who has gained the Awareness through the purification of the mind and the clarification of Buddhi (Intellect) will have the unchanging Bliss of Mergence in Paramatma. He alone can become Omniscient, who is ever in the region of Akshara (undecaying), merged in the Akshara (imperishable) Parabrahman (the Supreme Vastness), the Paramatma. When he is aware that all is He, that there is nothing without him or outside Him, he becomes all or Brahman. In deep sleep, the Jiva is in Tamo guna or dull ignorance. To the realised person, however, even dreams will award as much bliss as the consciousness does while awake. Even when awake, the person gets rid of the impact of the body-sense-reason complex and is saturated with the bliss of his authentic Reality. The particularised self shares the Chaitanya or Consciousness of the Universal and it can merge only in that Paramatma, the Supreme Chaitanya. Therefore this Sutra emphasises for us the truth that the ‘Sat’ or ‘Isness’ (which becomes and subsumes all creation) refers only to Parabrahman, the supreme consciousness and not to any entity derived from it and dependent on it. (Sutra Vahini, pp. 53-57)