Ivy has never had bad dreams before. She's probably the only person in Britannia with these memories who hasn't, and it isn't that she doesn't dream about it, just that her dreams are usually quiet, almost insignificant; her husband and children, her forest, happy or mundane things. But this night is different.
What she dreams about is Gawain dying, and how it ran through her body like an electric shock, like a lightning bolt striking a tree into flames, like a shovel thrust into the earth, like an axe blade into a trunk. It hurts: she wasn't there for it, but she felt it anyway, and it hurt like nothing else she ever experienced, and it hurts now.
Ivy has had little shields up to hide her magical activity for ages now, ever since she realised she had it. She doesn't shield herself from other people's, as she's trying to monitor Britannia's magic content a bit, but she tries to hide what she's doing from the sort of magical party line. When that death strikes into her, though, she retaliates with a piece of magic that's stronger than anything she's ever done before. It's like a replica of the same feeling, the same fierce piercing hurt, and anyone in the town and its outskirts who
doesn't have shields of their own is going to feel it. It isn't subtle, it isn't pleasant, and it pretty much blows any cover she had going.
It doesn't wake her up immediately, though. That comes a few minutes later, when she sits up in bed and reaches for Ken frantically, feeling feverish and empty and no idea why.