I recently visited a Sunday School class were this very thing was discussed. It was interesting, to say the least.
The consensus was that the miscreant male was somebody who was pretty important, possibly even a member of the group who was in such a big hurry to get her stoned and kill the evidence.
Of course, that doesn't make it so, but it would certainly explain the clamor for swift "justice" and the melting away after the brief statement of Jesus.
The other person didn't ask for forgiveness.
We do not know what happened to either of them.
We do not know if the woman took advantage of the
opportunity to repent.
We are all given an opportunity to repent, but
it is up to us if we take advantage of the opportunity.
I was in 7th or 8th grade and that Gospel was preached and I remember asking the exact same question. Quite a few people were shuffling their feet and staring at their shoes.