There's a difference between "the answer to the Fermi Paradox is that intelligent life destroys itself" which is what Venat knew before entering Ktisis Hyperboreia.

And "there is a gestalt conciousness at the edge of the universe, actively trying to kill us by sending the suicidal despair of dead worlds towards us." which is what she knew after.

It's reasonable for Venat to believe that one is going to cause more panic than the other.