• mithilāyām — at Mithilā
  The kingdom of King Janaka — a place of immense Vaiṣṇava significance. Gauḍīyas note: the same Mithilā that gave birth to Sītā now hosts Bhagavān's act of dharmic justice; the geography is doctrinally loaded.
• patitam hayam — the fallen horse
  Past participle of √pat (to fall) + horse. The verse's central image: the boasted vehicle is now a corpse on the road. Gauḍīyas pair patita-haya with Jarāsandha's viratha-status from verse 12 — same pattern, smaller scale.
• santrastaḥ — thoroughly terrified
  Past participle of sam-√tras. The intensified terror — santrasta, not just bhīta. Bhāgavata escalates the fear-vocabulary as Kṛṣṇa closes the distance: bhīta (v. 11), then santrasta (here).
• ruṣā — with anger
  Instrumental of ruṣ. Bhagavān's krodha appears — but Gauḍīyas read Kṛṣṇa's anger as instrumental: ruṣā here is the rod of the īśvara, not the fever of a wronged jīva. He is angry on behalf of dharma, not on His own account.

The hundred-yojana horse collapses in a Mithilā garden — the props of pāpa fail at the moment pāpa most needs them. Bhagavān continues on foot; the verse stages the truth that no vehicle delays the Lord when the rider is to be caught.