In The Force Awakens, after Rey had escaped from the interrogation chair (and beat him in a contest of the Force), Kylo Ren said to one of his stormtroopers:
"She's just beginning to test her powers. The longer it takes to find her, the more dangerous she becomes."
What I want to know is:
1) Why was this? Did he believe that the longer Rey stayed on the planet, the stronger she grew in the Force?
2) Did Rey draw her powers from the kyber crystals within the planet?
3) If so, how did he know this? Had he experienced the same himself?
Furthermore, why did Kylo reveal this information to a stormtrooper? What was she supposed to do about it? The trooper surely sounds like a female so maybe, out-of-universe, at some point of production, he was supposed to be telling this fact to Captain Phasma...?