My takeaway was that it triggered an instinctual reaction in N'Jal like it did with Batel. I thought that the intention was that the M'Kroon had a genetic predisposition to run away from the Vezda-Pah, like the Gorn had the instinct to attack.
I think it was more that he recognized what the living statue was, and it was something VERY scary in the myths and legends of his people.
Kinda like:
"Hmm. An ancient structure built by my ancestors. How very interesting and excitng." Explores a little further, spots a certain glowing idol. "Holy crap, this is the Unholy Temple of Cthulhu! Get me the hell out of here!"
There's ancient ruins of uncertain purpose -- and there's suddenly realizing that this ruin is the Hellmouth.
