@buiquanghuy12a2 Where do you think you lost it. The premise is they were talking about people and specifically Yotsuba getting blown away if they opened an umbrella. When she stood up and complained about the bread from the previous chapter, they thought she went to the bathroom. But both simultaneously came to the same conclusion, Yotsuba is specifically they type of child that would test the theory and see if she could get carried away. We see it from the Exclamation expression from her when they were talking.