Everything Landon said was indeed uncomfortable and disturbing to their ears.
From all they knew, there might be no evil coming their way, or perhaps those 2 places were the good guys while the seemingly carefree brat before them was the one they should truly be worried about.
In truth, they will never truly know unless they see it firsthand and explore the outside world.
That said, even if this brat was walking them into a trap, they still had to consider the fact that he might be telling the truth.
If you drove him away, he might bring more backup to attack them (if he was a villain).
On the flip side, if he drove him away and he indeed never returned to attack them, then you'll know he was telling the truth, but now… with your potential ally gone, you will be sitting duck, waiting for the day those 2 forces join hands to attack you.
And when that day happens, who knows what crazy technologies the enemy will have to crush them?
