Matsya Purana — Nārāyaṇa as Haṃsa in the Cosmic Ocean: Vedic Yajña-Puruṣa and Mārkaṇḍeya’s Vi...
स चिन्तयंस्तथैकान्ते स्थित्वा सलिलसंनिधौ पूर्वदृष्टमिदं मेने शङ्कितो देवमायया //
sa cintayaṃstathaikānte sthitvā salilasaṃnidhau pūrvadṛṣṭamidaṃ mene śaṅkito devamāyayā //
Thus, pondering in solitude and standing near the water, he took this to be something he had foreseen before—yet, unsettled, he suspected it to be the divine illusion (māyā) of the Lord.
It shows the psychological prelude to Pralaya: Manu senses a familiar, foreseen sign near the waters and suspects a divine orchestration (deva-māyā) behind the unfolding events.
It models prudent discernment: a ruler/householder should reflect privately, assess signs carefully, and recognize that extraordinary events may require humility before divine order rather than impulsive action.
No direct Vāstu or ritual rule is stated; the main takeaway is the motif of “salila-saṃnidhau” (near water), often treated in Purāṇic contexts as a liminal, omen-bearing setting for vows, contemplation, and major turning points.