A second simile, darker than the first. Moths do not know they are flying to their death. The flame draws them with irresistible force, and they rush in at full speed — 'samriddha-vegah' — not slowing, not hesitating. In exactly the same way, beings pour into Krishna's mouths to their destruction.
The river simile in the previous shloka carried a hint of return — water merging into the ocean. The moth simile carries no such softness. A moth that enters the flame is consumed. Arjuna's second comparison strips away any comfort and lays bare the raw fact: these beings are heading for annihilation, and they do not even know it.
Together, these two similes — the river and the moth — capture both faces of Time. One face receives everything back into itself. The other face burns. Both are true at once. Arjuna, standing between them, can only watch.