। ॥
In plain words
So the cause is unreal? Then go ahead: get the work done by the son of a barren woman. And drink the water of a mirage to quench a raging thirst.
Close to the Sanskrit
Saying, 'the cause is unreal' — let him accomplish the effect by means of the son of a barren woman; and what is more, having drunk the water of a mirage, let him quell a mighty thirst.