• dagdhvā — having burned
  Absolutive of √dah (to burn). A single past-active form for the destruction of an ancient city. Gauḍīyas note the Bhāgavata's lexical restraint — Vyāsa does not elaborate the burning; he names it and moves on, because the disc itself moves on.
• sudarśanam — Sudarśana
  Literally 'beautiful-seeing.' The name's etymology is the chapter's quiet joke: a 'beautiful-seeing' weapon that has just rendered a city un-seeable. Gauḍīyas resolve the irony: Sudarśana is beautiful-to-see for those who see Kṛṣṇa in it; only the offender sees fire.
• pārśvam upātiṣṭhat — went to His side
  Phrase: pārśva (side) + upa-√sthā (to stand near). Returns to the same standing-position from verse 38. The chapter's frame: Sudarśana at His side, mission, side again. The disc's permanent address is Kṛṣṇa's shoulder.
• akliṣṭa-karmaṇaḥ — whose actions are without trouble or fatigue
  Compound: akliṣṭa (untroubled, unfatigued) + karman (action), genitive. A favorite Gauḍīya epithet of Bhagavān. Akliṣṭa-karmā — the Lord whose works cost Him nothing. He fought a duel, dispatched a disc, burned a city, and the verse names His action 'without trouble.'
• bhūyaḥ — once again
  Adverb. The 'again' that closes the chapter's circle. The disc went out; the disc came back. Gauḍīyas note: the entire chapter rhymes its returns — Pauṇḍraka's words return to him (verse 19); the kṛtyā returns to its summoner (verse 40); the disc returns to the Lord (this verse). The pattern is the chapter's signature.

• Where am I straining to do what Kṛṣṇa could accomplish through me effortlessly?
• What would relaxed cooperation with the Lord's will feel like today?

An obedient son finishes the errand and returns home — Sudarśana, having burned a city, comes back to stand at the Lord's side as quietly as it left. The disc's silence at return is part of its terror: it does not ask permission, does not boast, does not linger; it does what is asked and returns.