Even up to this point, Leah is still taking in the fact that these guys are originally fictional characters from a book - heroes who were summoned to protect peace and order in this school.
It's a good thing that they trust her ability enough to let her take part in this mission. There's also the fact that they started treating her as a comrade and not just an outsider anymore.
But then, seeing these two Student Council members all transformed into their Champion forms, she recalls just how life-threatening this choice is. Those harrowing memories back in the Atlantic Realm are still alive and vivid in her mind, and now that she's in a similar situation for the second time, she can't help but worry a little - not really up to the idea of witnessing any danger to befall her friends again.
"Oh, what's this~? Are you scared, Young Miss...?" Noah suddenly chimed in with a teasing grin, making her snap out of her running train of thoughts.
