Madoka is so caught up in thought about everything he's saying that it's almost as if she snaps out of it a little when he tells her to look him in the eyes. Her eyes are a little wide, the look in them still obviously worried - he should be able to see it just fine, exactly because they're looking each other in the eyes from up close like this.

"Me?"

It doesn't feel right. What can she do in this situation? Sure, she is the one who took the mana drive along, but anyone could use that! She could've passed it on to Yondu himself and he would have been able to use the spells, she's sure.

But Madoka thinks maybe he's just trying to cheer her up. And in that case it'd be rather rude of him to just refuse his encouragement, right?

"I-I'm not so sure of that.. I mean, I'm going to do my best!" Because she doesn't want him to get the idea she's giving up. She's not, not at all, because she really does want to help everyone. "But there's not so much I can do.. It's up to everyone out there to keep the city safe, right..?"