After showering and having dinner, Nero and the rest went to an isolated area where it was okay to meditate and expel impurities. Just in case, Elsa was around to protect them should something happen.
Nero, in turn, did not know how to do this in front of her sister's surveillance. After thinking, she decided to do it even with Elsa watching. Nero's instincts confirmed that she could trust her, although she didn't want to explain too much. It would be better if Elsa knew as soon as possible.
'Actually, I think she already knows...' It wasn't the first time Nero had been watched by Elsa. If she didn't ask, it was because the degree of trust she placed in Nero was higher than she imagined, to the point of waiting for Nero to tell her of her own volition without having to ask.