The exposure of her mind was always a risk, and until Hermione could replace her own mental shields, she was vulnerable. And as Enola felt responsible for making her defenceless, both in proposing the plan and having to magically sedate her later, she felt duty-bound to fight Hermione's battles for her. So with each attempt at incursion, Enola would cast another barrier, put in another block. It was working so far, but she had to hand it to that fucktard Weasley ... he was a persistent little shit.