"I've got an idea," the Doctor says, as Abigail looks over at Dr. Bloom. "You keep on shopping, I'll stand between you and the ghost until you finish. That way you won't have to look at her."

Because obviously this is bothering her. And there's no way to make these ghosts actually go away, but there are ways to keep Abigail from looking at them.

As if to prove his point, the Doctor attempts to move in between Abigail and the mirage, trying to block Dr. Bloom from her sight.