Sakura: Yes, Master?
Tsunade: I read the mission report.
Sakura: (Looks down) I'm sorry... I wasn't strong enough, I was nothing but a burden...
Tsunade: Tch. Stop your snivaling!
Sakura: (Looks up; shocked) Tsunade...?
Tsunade: (Stands up; slams palms on desk) It's time Sakura... Time to grow up! Starting today, your gonna train your butt off!
Sakura: (Dumbfounded; smiles) Yes ma'am! *I have to become stronger to protect Naruto!*
___
Actually given shonen tropes and the themes of the manga to date it may very well be exactly something like that. Tsunade firing up Sakura by reminding her of her promises to naruto, and pushing her harder then before.