I know she's an unimportant side character, but...

Sometimes, I look at foolish villains and while most of the time I just point, laugh, or ignore them, this time I couldn't help but wonder what the girl had in mind when she was sent back... she did know that no matter how much she wanted it, if she's not the chosen one, then she's just another regular person, right? I mean, it's pretty obvious, but I was probably impressed by the gall to be violent to the guards instead of acting cute like before (probably tried that and it didn't work.)

I can clearly guess what she's thinking at the beginning. She wants to be special, simple as that.
If she was a heroine, she gets to live a great life, be catered to by everyone, and so even if she had no powers or anything, perhaps she'll make up for it somehow. But even if she's oblivious, if the guards are capturing you and you were told you'd be sent back and that your summoning is a mistake, you'd understand that you're unwanted.

Is she resenting the salaryman for being the chosen one, when clearly she's more MC material by her standards? If she did manage to stick around by using sheer force of will (she was violent and had to be subdued in order to be sent back), what was she intending to do? She can't play the "I'm cute and innocent" card any more. For sure she'll desperately appeal her good points here, foregoing all of the things she lacked, what she nearly did to the actual summoned person, or perhaps claim that he stole her powers or something. She intends to reap the benefits without exerting any effort, even if she knew the world's dilemma. She had been that way from the very beginning when she forced her way to the summoning circle, after all... Push comes to shove, she'll just make excuses after excuses if she's unable to perform.

And when she returned to her world, what did she think? Would she force her way into this time making a portal for another world? And if she managed to return, I think this time she'll antagonize the world, for "mistreating" her. But knowing her, she likely won't accomplish that, and if she enlisted the help of someone talented or knowledgeable, she's still the same talentless individual so I don't think she'll get very far. She'll probably continue resenting everyone in there, until she finally realizes it's completely and utterly impossible. Time has a way of wearing down a lot of sparkly-eyed dreamers, so by then I think she'll mellow down and simply think of it as foolishness - that she'd be better of spending her time on anything that won't get her sent out into her old world... like perhaps enacting the same stuff in real life. If she can't be a princess in the fantasy world, she can be a princess in the real world.