1. During the 'rumbles' that still come around every few hours, she will sense that all magic kind of shorts out for half a second. Everything feels a bit chaotic, like any rules that should apply to magic don't seem to apply here. There will be pockets of a lot of energy, and then ten feet away nothing at all. There's no real pattern or reason behind any of it.

2. Yes that is completely okay! Just keep in mind that the groups will not be able to interact. If she senses it and says 'I don't trust it, let's go in this other direction' that is okay. If she or anyone else tries to convince them to follow after it, no matter how they try or which hallway they turn down, they will never be able to actually find them.

3. The beast will never let her get close enough to do it. It is almost as if it knows of her power and will directly avoid it.