The fairies were slightly taken aback by Lex's impatience, as well as his willingness to help them out so easily. In their defense, they had a very long time to imagine being saved from their grim fate, and this definitely did not reflect what they had imagined.
First of all, the moment that they realized that the destined savior was a human, they felt a slight bitterness. They did not expect a human to work against his own race for their benefit. They also did not want to associate any positive feelings for the race that was responsible for trapping them to begin with.
But he just seemed to be concerned about getting into the final chamber. He neither cared for the great secret of the domain, nor what they would offer him in exchange for their help.
"The heart of the domain is a treacherous place," the armored fairy tried to warn Lex. "It is surrounded by powerful beasts who will not be cowed by the aura of your projection, and by a treacherous environment."