You chose to take Quentin to talk with a grown-up that you trust who will help to convince Quentin not to do this. Quentin could be arrested if he did not stop. When someone breaks into a computer, it is often very expensive to fix the computer and make sure that it doesn't happen again. By telling an adult, and preventing Quentin from breaking into the school computers, you have probably saved your school a lot of money, which they can use on other things like new sports equipment, or even new computers. You made a good choice.
Hackers destroy property and records.