दूष्याननुप्रविष्टा वा तीक्ष्णाः शस्त्ररसाभ्यां हन्युः ॥ कZ_०९.५.१५ ॥
dūṣyān anupraviṣṭā vā tīkṣṇāḥ śastrarasābhyāṃ hanyuḥ
Or, sharp agents who have infiltrated the compromised persons should kill (the targets) by weapons or by poison.
It represents escalation when conciliation/co-option fails or when the threat is acute; Kautilya presents a graduated toolkit.
Two covert modalities: overt-looking violence (weapon) or deniable killing (poison), chosen for feasibility and concealment.