Ive jsust noticed:
The character Majestic is Ja Rule. He wanted Marcus shot, and when he found out he wasnt shot, he killed 'Justice' - the gunman. In real life, 50 says Murder Inc had ahitman try and kill him but failed, and that hitman died 3 weeks later.
Majestic is also managinga rapper called 'Dangerous' and Majestic labels Marcus a snitch, just like in the real life case with Murder Inc.
The chapter of the DVD just before Marcus goes on stage at the end is called Rule 5: Dont show love. This seems to obvious.
The Marcus has him shot in the head. This is as if to say that he would have done the same to Ja if he had the chance.