In this series, almost every criminal said, "I had no choice/ I don't know what else to do/ I can't let this ruin my life...", and they don't even show a little bit of repentence. Especially Donna, the right choice was getting away from her abuser, but she killed an innocent girl instead and made one more innocent person gone in prison for 23 years. After all that she could still get out of prison to die at where she wanted and act like she was the victim. Ultimately she could finish her revenge, and leave all the mess behind her death. Same for the ones responsible for Marie-Ann's death. They've lived too many good years. It's too easy to commit a crime, and too less to pay.