I had to rat on someone for the first time ever

You did what you felt you had to do, kudos for taking a stand. That being said, I have found over the years it is best to just stick to what is your job description. If you're not a manager then don't get involved in what you think is best for the department.

Remember you are working for a big machine, all kinds of stuff goes on, and they can get rid of you in a heartbeat.