Maybe the back story of his parents and upbringing will be told, and this is how the redemption of Mason will be achieved, so that he he stays in the programme. He'll return after serving his sentence, fully repentant and rehabilitated, ready to become "one of the nice boys".
And as seems to be the case with other criminal behaviour on the Street, he'll be welcomed with open arms. Probably end up living in Eileen's tardis