"Keep alert to the surroundings, there's a mole inside the Humming Damned Forest"
While they were coursing through the forest, heading to the Dark Elf Kingdom, Flunra can't help but warn the Dark Elves knowing that there was a looming threat from the Witch of Chaos hiding somewhere in this ominous forest.
It was not his fault, but he partially blamed himself for the awakening of the Executor.
Flunra was the one that confronted Dealkandrax right in front of the castle yet he fails to understand the potential threat the Witch of Chaos possesses, he underestimated them too much as he had already fought them numerous times throughout his life.
As he has the means to deal with the cursed creatures, he was never scared of them.
But the Witch of Chaos probably used the fact that he was underestimating her to kidnap Kyran, she expected that Rex and the others wouldn't expect it knowing full well that Flunra doesn't seem to be worried about her.