• brahman — O brāhmaṇa
  Vocative — Parīkṣit addresses Śukadeva. The king under death-sentence is, again and again, the model śravaṇa-practitioner: he asks, the brāhmaṇa speaks, the seven days of the Bhāgavata unfold. Bhakti is sustained by exactly this circuit.
• vīryaḥ — powers
  From vīrya — heroic potency. Mucukunda has vīrya enough to incinerate an asura with a glance, but the rest of the chapter will show that his real vīrya is the strength to refuse all boons except service. Two senses of vīrya laid side by side.
• guhām — in the cave
  Accusative of guhā. The cave will keep returning — it is geography, refuge, and tomb, but most importantly the temple of Mucukunda-stuti. Bhāgavata caves often house transformations (Jaḍa Bharata's, Mārkaṇḍeya's, Mucukunda's).
• yavana-ardanaḥ — the destroyer of the Yavana
  Compound: yavana + ardanaḥ (afflicter, killer). Parīkṣit already names Mucukunda by what he did, before knowing who he is. In Bhāgavata pedagogy, action precedes identity in the storytelling — fitting for a tradition whose central category is līlā.

A child watching a thunderbolt strike across a field, then turning to the grandfather: 'Who was that man, what was his lineage, why was he asleep?' Parīkṣit's questions are not idle — they are the Bhāgavata's pedagogy. Every great līlā opens out into a back-story so that the devotee can learn the chain of causes.