Matsya Purana — The Slaying of Jambha and the Rise of Tāraka: Divine Battle Formations
रथादाप्लुत्य धरणीम् अगमत्पाकशासनः मुद्गरो ऽपि रथोपस्थे पपात परुषस्वनः //
rathādāplutya dharaṇīm agamatpākaśāsanaḥ mudgaro 'pi rathopasthe papāta paruṣasvanaḥ //
Leaping down from the chariot, Pākaśāsana (Indra) went onto the ground; and the mace too, clanging with a harsh sound, fell upon the chariot-seat.
This verse does not discuss pralaya; it is a battlefield action detail describing Indra dismounting and his mace falling with a harsh sound.
Indirectly, it supports Rajadharma/Kshatriya ideals: composure and readiness in conflict—symbolized by a swift dismount—while also highlighting the chaos of battle where even a weapon may slip and fall.
No Vastu or ritual procedure is stated; the only technical detail is the chariot-seat (rathopastha), a narrative element rather than an architectural prescription.