[Mami instinctively tenses when Utena begins to walk, the other girl's body moving beneath her. Her other hand grips Utena's shirt where it covers her shoulder, tiny fingers digging in. She's slow to relax as she considers the question.]

I don't think there's any cause to worry. It might be dangerous, yes, but the outdoors contain far more threats....and this magic will only be temporary. Better to pass the time inside than not, I'd think.