Benon gave up trying to build a trebuchet, not enough Redwallers would help, he would help direct fire for the balistae. The vermin were panicking, having fire shot at them had made them move closer, just within range of the Redwaller's bows. He unstrung his longbow and let arrows rain into the enemy's ranks.
For hours the battle went on until the vermin horde retreated a few hundred yards back along the road. They stopped to lick their wounds and asses the casualties, well, those with enough sense did anyway.