It's a bit awkward having to constantly move to keep the ghost out of sight, but the Doctor does it with ease. The fact that he's a good six foot tall is pretty helpful in keeping the ghost out of view.

But if Abigail wants to go to a different store, well then they'll just go to a different store. "Lead the way!" the Doctor responds, with a little nod, as he takes a step to the side to further keep ghost-Alana out of sight.