• avidūre iva — as if from nearby
  A-vidūra (not far) + iva (as if). Kṛṣṇa was at a great distance, yet closes it 'as if' He were close. Gauḍīyas read: Bhagavān is never functionally far from His devotees' enemies — geography does not bind the protector of the prapanna.
• durātmanaḥ — of the wicked-souled one
  Dur (bad) + ātman (soul, self). The demon is durātman — not because his ātman is intrinsically corrupt (every ātman is part of Bhagavān) but because its embodiment and conduct are. Gauḍīya tattva: jīva is eternally Kṛṣṇa-dāsa; corruption is in the upādhi.
• muṣṭinā — with the fist
  Muṣṭi = clenched fist. Kṛṣṇa kills Śaṅkhacūḍa without weapon — His hand alone. Gauḍīyas mark the rasa: the same hand that pulled at Yaśodā's saree, lifted the butter, played the flute, here ends a demon. Bhagavān's body is multifunctional grace.
• vibhuḥ — the almighty, all-pervading Lord
  From vi-√bhū = pervade, become great. Vibhu in its highest sense applies only to Bhagavān (Śiva in v. 2 was vibhu within his jurisdiction). The verse closes the demon's chapter with Bhagavān's true title, leaving no ambiguity about who acted.

• What threat feels too 'far away' from the Lord's reach in your imagination?
• Where have you mistaken distance for absence?

From a great distance — but as if from arm's reach — Kṛṣṇa overtakes Śaṅkhacūḍa and removes his head with a single fist, jewel and all. Bhagavān's reach is non-Euclidean; the bhakta-protector is everywhere His own are threatened. One fist for one demon: no over-engineered weaponry, just the hand that once held butter.