[For the first time, the girl's words are helpful to Saber-- it'll be a test of her patience, but if others are coming, perhaps waiting this out defensively in a stalemate is the wisest option. She doubts the girl will actually fire at either of them, so she really only has to worry about the enemy Servant becoming desperate and stay just as she is to be ready.
Not attacking, not backing down, not making a move at all]