Okay well, I don't have any definitive ideas but as a baseline, maybe we can work from this?
Crystal (my teacher character) puts out a request for a dangerous mission, one that she will oversee. If you want, Monster, we can throw in that your teacher will also be coming along to make sure the students don't get hurt.
Lissa carelessly accepts the mission on the team's behalf, not even running it by the others first. She just assumes they would all go along with it and gets overly excited.