In this scene, on the left you can see Lexie before she stopped going to "the hangout". You can see that she was trying to act and look more grown up....But on the right side you see her after she learned to live in the moment. She was back to being herself, and she acted that way too. Lexie learned to live in the moment.
In this scene, you see Peter, worrying about Mr. Terupt and his "dizzy spells." Peter soon learns, though, that he should live in the moment, and not worry about what might happen to Mr. Terupt in the future because of his injury. Mr. Terupt teaches Peter to live in the moment.