Frank O'Connor, Franchise Development Director at 343 Industries, makes a cameo appearance as a janitor at the academy. He is seen in a crowd spectating a fight.
Who's the best shot here?
Michael Sullivan: You, probably?
When Lansky and the other students ask the stranger for his name after he saved them, John-117 tells the students that his name is Master Chief. But at this point, he was still a Chief Petty Officer and he should have said Chief. He didn't have the ranking of Master Chief Petty Officer yet.