[She instinctively begins the motion to go after her, before stopping completely stunned. That woman honestly knew her; how many Heroic Spirits could identify her, after all? But from where? Saber's certain she would remember meeting a beautiful woman like that, no matter the circumstances at the time]
[But the black Servant is gone now, and gathering her wits again, she can finally turn to help the people most important at the moment. There will be plenty of time later to contemplate things]