It probably doesn't matter to them now that she didn't know where this was going. It's not something that came to her until much later, when she was thinking over the list of spells and realized what they would mean together.

"I've tried. I've tried breaking the spells, I've tried finding the thing itself, but I'm running out of time. There's one more thing I haven't tried, but I wanted to warn you before - "

She hears the shattering glass before she realizes anything else, the sound of the window behind her breaking. It seems discordant, almost, as though that wasn't the thing that was supposed to happen in that moment, but it isn't until she looks down and sees the arrow sticking out of her chest.

Oh.

That saves her some trouble doesn't it?