The impression born from that obstructs other impressions.

Direct knowledge (ṛtambharā prajñā) generates its own saṃskāras — impressions that are of a different nature than ordinary ones. These new saṃskāras block (pratibandī) the old saṃskāras that perpetuate the cycle of mental fluctuations.

It is a process of substitution: impressions of ignorance are gradually replaced by impressions of direct knowledge. Fire against fire — using the mind to transcend the mind.

However, even these liberating saṃskāras are still saṃskāras. The final step requires eliminating even these seeds of liberation, as described in the next sutra.