• ākṣepam — the insults
  From ā-√kṣip (to throw at). The exact word for sharp counter-speech, especially in debate. Kṛṣṇa's reply is classified as ākṣepa — a recognized rhetorical move. The Lord knows the genres of speech and uses them deliberately.
• svāmine — to his master
  Dative of svāmin (owner, lord). Bhāgavatam quietly tweaks the diction: the messenger's 'master' is Pauṇḍraka, a man whose mastership is fiction. The real Svāmin is the one whose chariot, two verses later, is already on the road.
• ratham āsthāya — riding His chariot
  Compound idiom: ratha (chariot) + ā-√sthā (to mount). Echoes the BG opening (rathopastha upāviśat). The chariot of Kṛṣṇa carries different cargoes in different chapters — a hesitant Arjuna, a returning Sudāmā, now an iron resolve toward Kāśī.
• kāśīm — to Vārāṇasī
  Accusative of Kāśī. The most ancient sacred city, presided over by Viśvanātha (Śiva). The chapter sets up the strange spectacle of Sudarśana eventually burning even Kāśī — because the city has sheltered the imitator and his abhicāra against Kṛṣṇa.
• upajagāma ha — He went near
  Perfect of upa-√gam with the emphatic particle ha. The ha gives the line a Vedic-recitative gravity: 'thus, indeed, He went.' The Bhāgavata writes the journey as inevitable as gravity.

• Dina Bandhu Pr SB 10-66-10-15 - 2015-05-22 ISKCON Alachua
  His Grace Dina Bandhu Prabhu· 2015-05-22· English

• Where am I avoiding a decisive step I know is needed?
• What is the difference between patience and procrastination in my life?

The chariot of Kṛṣṇa is not a vehicle of conveyance but the moving courtroom in which His verdicts are executed. The wheels that bore Arjuna at Kurukṣetra now turn toward Kāśī — the geography of the world is rearranged around the Lord's mission.