I love this because Larian got wise to my shenanigans since the pre-release. I didn't think there was an easy way to keep her from retreating to her basement anymore
In the pre-release days
you could just corner her or block the entrance to the basement (after a successful perception roll) with your party or the environment and keep her trapped upstairs.
Looks like they have given her...misty step...if I remember correctly, so she'll just slip away into the basement if you're not able to put out enough damage in a single round