No way in hell were they empty.
Depending on where they were administered, the nurse, Dr, or pharmacist would have to draw it up into a syringe since they are multi-dose vials.
I have never seen saline in a vial, though I suppose it COULD be available that way.
Kroger would not have had it in vials. It makes no sense that a grocery chain would carry that in their pharmacy.
Who the hell would be injecting saline at home?

Their explanation is bullshit.