। ॥ १०४ ॥
In plain words
She runs on like night, with no end anywhere in sight, and here nobody can make out what she actually is. Yet the instant the sages look straight through her, she is gone — a flash of lightning, and nothing.
Close to the Sanskrit
Endless like the night — her own nature is not discerned here; like lightning she perishes, the very instant she is closely examined by the sages.