Meng Qi did not enter recklessly before fully knowing the condition of the whirlpool. He utilized his Dharmakaya, condensed his Divine Sense and formed indelible rays of mild golden light which then flowed like water and extended into his body.
With a boom, his Dharmakaya shook and his senses were no longer the same. The interior of the Dim Whirlpool was a boundless vast, Chaotic Holes formed by perishing collapses were everywhere. The holes were near to each other, devouring each other and grew constantly. It was magnificent yet scary.
More importantly, all those endless elevations seemed as if they were falling down, collapsing and falling apart, which lowered the legendary nature throughout this boundless and gloomy precinct. As such, he could not depend on Dharmakaya alone to be ubiquitous and view the whole place in order to find the clues.