John 8:9

And they, when they heard it, went out one by one, beginning from the eldest, even to the last: and Jesus was left alone, and the woman, where she was, in the midst.

The Saviour's silence, the total absence (or silence) of any witness against the woman, and the watchfulness of the mighty throng surrounding the little circle of Pharisees with Jesus and the woman at the center - all of that became suddenly a situation of profound embarrassment to the Pharisees. The oldest, being the more perceptive, led the way, and they all left. Once more the Galilean had conquered.