Celeste looked at Jack, at first worried about him getting hurt, but then remembered that the rock probably didn't even scratch him due to his abilities, but now the glow coming from his clenched fist was much more worrying. Imagined visions of chaos and destruction rushed through her head and she quickly went towards him, only to nearly be knocked down by the sonic boom he created. Managing to regain her footing, she looked towards the crowd, and then back at Jack, hoping that he knew what he was doing. This might be interpreted as an attack by them, and she feared they try to come up and hurt him even more.
Instead, what came next was a speech. While she didn't quite know what 'The American Way' might be, what he said and the way he said it made him seem wiser beyond his years, something that had been said of her often. She was silent with the crowd. He didn't seem to be finished, and she didn't want to interrupt.
When he finished, she stepped forward again, "Please, do not judge him on that he's a foreigner, but rather, from the way he acts. If you really must, you can take how he acts as a representation for Earthlings in general, I can only hope that they have some of the same virtues that he has. ... Though perhaps not the abilities, I'm fairly sure that Earthlings don't have the same capabilities."
The crowd continued to stare for a moment, one person shouting out, "Well yeah, just, um..." before slinking away, and eventually the rest of them went away as well, leaving with barely any damage done.
Celeste looked up at Jack, sighing a breath of relief, "Thank you so much!" she said, going out of her usual tone of voice, "Usually these sort of things end violently, and for you to calm the crowd like that, I can't even describe how relieved I am about no one getting hurt, or having others dragged into this..."