Into the bathroom

"Er... You might wanna change in the bathroom." Fumiko turned around and started walking. "Well, before you enter the bathroom, please put on some of the shoes that are at the door, in Japan it is ..."
"I know ..." I interrupted her. "Here there are special shoes for the bathroom, which dates back to the time when the toilets were outside the houses and you did not want to drag the dirt from outside into the living rooms.
Fumiko stopped, turned around and looked at me, kind of puzzled. I was not sure if she was embarrassed, that I already knew about it or if I was just rude because I did not let her finish.
"Oh, um ... I've been living in Japan with my parents for a couple of years now, so I'm familiar with the customs here. I did not mean to expose you."
Fumiko's face relaxed again. She handed the things to me and showed me where the bathroom was. I changed my shoes and went inside.
"I'll need a little longer," I apologized in advance. Because I realized that I hadn't used a toilet the whole day.
A few minutes later - I had just taken off my clothes and wanted to put on the things of Fumiko's brother - there was a knock on the door.
"Are you okay in there?" I heard Fumiko asking from outside ...