• ghātayiṣye — I shall have (Them) killed
  Causative future of √han (to kill). Kaṁsa makes himself a remote cause — he will have it done, not do it. Even his violence is delegated; the only thing in his palace that is direct is the truth Nārada brought.
• kāla - kalpena — like time itself, like death itself
  Kāla (time) + kalpa (resembling). The elephant compared to Kāla, devourer. Yet in five chapters Kṛṣṇa kills Kāla-like Kuvalayāpīḍa with a single twist of the tusk — Kṛṣṇa is the kāla of Kāla (kāla-kālaḥ).
• hastinā — by the elephant
  Hastin — elephant. The kingly weapon. Mathurā's signature instrument of state-power, deployed at the arena-gate.
• vaidyuta - upamaiḥ — comparable to lightning
  Vaidyuta (lightning) + upamā (likeness). The wrestlers' strength is named with Indra's weapon-image again — same image as verse 10's thunderbolt. The Bhāgavatam keeps recycling Indra-similes for Kṛṣṇa's opponents, since Indra Himself was already conquered at Govardhana.

• What 'backup plans' do you keep against the conclusions of your own spiritual life?
• Where could you trust that Kṛṣṇa would pass through all of them anyway?

If the elephant fails, the wrestlers; if the wrestlers fail, the next plan. Kaṁsa lists backups for Bhagavān's murder. Every plan is correct in form and impossible in fact. The Bhāgavatam smiles at the cumulative redundancy of an asura against the Lord.