Translation
Upon hearing [these words], and because their consciences were being rebuked, they began to leave one by one beginning from the older ones to the last [ones], and He was left alone and the woman who was in the middle.
Paraphrase
Upon hearing the words Jesus said, and because their consciences were finally feeling the rebuke of His actions, they began to leave one by one beginning with the oldest ones and on down until the youngest ones had left; then Jesus was left alone with the woman who was still standing where she had been placed – between Jesus and His listeners and in the middle of her accusers.
WHY DID THEY LEAVE IN ORDER?
I believe the reason they walked away in order of oldest to youngest was that, as a matter of respect, the oldest one there was the one responsible to speak on behalf of the group. When the oldest one could not defend his life and his actions he walked away, leaving the second oldest in charge and faced with the same dilemma. The second one also came to the conclusion that there was no way to respond to the rebuke of Jesus without digging himself into a hole, so he also left. This repeated itself until all of them were gone and the woman, who had been standing there the whole time, was the only one left.
As I envision it, the people who had been listening to Jesus had formed a ring around the religious leaders so they could see what Jesus was doing. Now, in order to leave, the religious leaders had to turn and walk right past some of those people who had gathered around them. Did the people open up a path for them or did they force these hypocritical religious leaders to push their way through the crowd? We don’t know. What would you have done? Because human nature is the same the world over, unless there were some cultural norms that are different than ours, it is likely that those people would have done the same thing you think you would have done. This act of having to make their way through a crowd in order to make their escape from the conviction and rebuke delivered by Jesus made the situation even more humiliating for those religious leaders.