Mia tapped her fists against his. She liked the idea of being able to let loose a little and she did trust Derek to tell her to dial it back if she went too far, and to do it without thinking less of her for it.
She didn't balk at the idea of being able to 'go first'. Instead, she decided to fake going left and went right, aiming a punch for his ribs. She was slightly familiar with how he might react after their first bout and figured he would block her, but that didn't make her any less inclined to go all out. Mia's style was much more attack first and find any opening possible instead of circling and waiting. She was more than a little impatient in that regard.