She closes her eyes, and imagines him here. Imagines him looking at the fish tank, inspiration striking, the gleeful expression as he calculates the pain he will cause. She imagines him, imagining her, telling Buffy what he’s done. He dwells on Buffy’s shock, her realisation at last that she can’t protect her friends from him. Everything he does, every torture he inflicts, is for Buffy, torn from the twisted leftovers of their love. He can’t think of anything but Buffy; he can’t do anything unless he does it for Buffy.
And part of Willow wishes it was all for her.