This scene is when Monica and Q are in college.

After Monica has won her first game as a started they go to a party. During the party scene Monica and Q are talking and then Q goes to get some beer. While he leaves Monica talks to Citra. When she leaves Citra she sees Q talking to another girl. She goes to talk to him and when she does the girl walks away. But heres the catch. When the girl walks away watch her because she is still looking back at Q and isn't watching where she is going and bumps into one of the extras who are dancing across from them. They try to divert your attention away from her but watch its there.