Ari: "I'm starting to think my parents are kind of the worst..."
Also, I like to think Matthias is trying to be caring, loving, and supportive here, but there's that part of his brain that's going: "Huh, dragon tears turn to vapor... that's interesting."
And YES! Some of you in the comments guessed correctly how that passage ended a while back, but just to clarify, it's being "CAPABLE" of slaying, not actual slaying.