-( Story related, cannot be missed )-
* Do not skip cutscenes!
In the destruction derby, you'll have to try and make it to Mo, but the Boom Boom Bros have her pinned and you can't get close to her. Drive over to the left ramp and wait until the orange car is on the other side before driving off of it. This will stall the vehicle and allow you to move it around safely. Bump it into the far southeast part of the arena, avoiding the BBBs (or else as they hit it, the orange car will start back up and drive away). Safely pushing the car to the right, you'll need to move it up the ramp found here, then follow behind it to meet up with your partner in crime.
After pulling off the plan, move to the far left and come next to the piping against the wall. This will start a chain reaction of fire to light the entire stadium up. Once the BBBs start back up, you'll find yourself standing on a vehicle to avoid them. Once they ram the vehicle, hop onto theirs and they'll start driving away. As they near the open fire, jump off and over to it which will seal their fate and eliminate the competition, so to speak.