Should I report the leakage?

TL; DR The class I belong to had a leakage and I was the only one who was not given the same; A lot of students from other sections have failed the subject and did not graduate and, clearly, it was unfair on their part and mine as well.

Long Post:

I'm a fourth year law student but I still have some third year subjects, so hopefully I will graduate next year. I was in this section for this semester in **** review subject. Our final examinations are divided into two, namely, the final exam proper and the departmental exam. The latter composes 40% of the total final exam score. It is a bunch of multiple choice questions.

Before the examinations started, I met my friend outside the room asking me if I received the "pdf", which contains the answers to the exam. I said no. As the exam already started, I did not have time have him send me the "pdf". I took the exam and found the departmental MCQ real difficult (final exam proper and deptals are taken at the same time). After the exam, I asked him to send me the "PDF". The "PDF" had 75 mc questions while our departmental exam had 40. All of the questions in the departmentals are in the "PDF" with answers based on the answer key.

Now, fast forward, the list of graduating students was released. A lot of students from other sections did not graduate. I looked at our online student site, and checked my grades as they are supposedly released already. Although no actual numbers on the individual subjects, I calculated my grade on **** review based on the shown GPA. Yes, I failed.

As to myself, I could just retake it next year and then graduate. But what about the students from other sections who failed, some of whom are my friends, and did not graduate because of one subject.

I'm torn between fighting for the right when I could opt not to and to just let it slide because although I might get benefit, I would have to go to war against the section.

Edit: If I'll be a snitch, I'll be risking myself and the whole thing may backfire to me. Also, the leak is from a lawyer who is a junior partner of the firm of our professor.