sañcintya - having thought; ari - their enemy; vadha - for killing; upāyam - about the means; bhīmasya - to Bhīma; amogha-darśanaḥ - the Supreme Lord, whose vision is infallible; darśayām āsa - showed; viṭapam - a tree branch; pāṭayan - tearing apart; iva - as if; saṁjñayā - as a sign.

Having determined how to kill the enemy, that Lord of infallible vision made a sign to Bhīma by tearing in half a small branch of a tree.