You can do this when you have a time limit in your challenge.

When you use a Gamebreaker 2, the timer will go down a certain number of seconds. Use your Gamebreaker 2 with 5 or so seconds left. The timer will run out in the middle of your gamebreaker. Select "retry" and you will continue with your Gamebreaker 2 even though you're supposed to start with no Gamebreaker meter.

WARNING: This may cause the game to freeze up.