Why Will GOHAN NEVER GO SUPER SAYAIN IN THE TOURNAMENT!?

Okay, so If you watch DBZ Super, you know he's aiming for a different form never seen before, Mystic Sayian I believe, because he hates when the S cells take over when turning Super Sayian and make him blind and cocky in battle, like Vegeta and Goku, even in their normal state.(When fighting Cell, is the greatest example) But why won't he risk it all? He'd be so much more powerful and could even possibly reach Super Sayian 3, let alone, FIGHT JIREN AND PUSH HIMSELF TO GOD LEVELS! I just can't wrap my head around this. It's Like the Seahawks throwing the ball and losing the game WHEN THEY'RE AT THE ONE YARD LINE AND RUNNING IT WOULD MAKE MORE SENSE!
Input and theories would really help, banding together to think of any possible reason he wouldn't do it to go back to Pan and Videl, because he is making me mad denying the full power the true Sayian form brings.