In the scene when Kip tells Napoleon that he is trying to become a cage fighter, he is typing on the computer. Then Napoleon tells Kip that he has the worst reflexes of all time, then Kip says come and hit me. Here is where the slip up is; Napoleon comes down to him and you can clearly see that the computer is turned off, but a minute ago he was typing on it.
So what? He could have easily turned either the monitor or the computer off. There are many different things Kip could have done to make the screen appear blank. Maybe he didn't want Napolean to see what he was doing.
Guy's, Kip had played it and pressed the button or something. He also could have READ THE SCRIPT and did what he was supposed to do. Maybe he was playing on the computer while it wasn't on.