Ending up with Medusa’s head gives Percy an easy way to deal with Gabe, since it will turn Gabe to stone if he looks at it. However, Percy isn’t as impulsive as he once was, which is, in part, because he no longer associates his impulsivity with ADHD. Instead, his new understanding of how his brain and body work helps him to control his impulses and make more nuanced, well-thought-out decisions. This decision, then, will illustrate how far Percy has come in terms of growing up and figuring out who he is.