The Hensleys are neighbours from hell.
Yesterday, she saw the power she could have to help people from Hell.
Her thoughts went to the good she might be able to do from Hell.
Deidre made a deal with the Dark One, one good enough to bring her soul back from the dead, combine the two Deidres, cure the tumor of one and release the final product from Hell.
Apparently, the portal isn't closed from Hell.
It happened the first time Darkyn invaded the mortal world from Hell.