Why didn't Mariam want any visitors at jail or witnesses in trial?

Mariam understand what she did and in her own mind can justify her reasons.... Rasheed needed to be killed. Mariam committed the murder. She had no need for witnesses or visitors, she believed that her impending execution was a legitimate form of death. In the end it wasn't about her..... it was about giving Laila a fresh start, a life with her children and Tariq..... it was about sacrificing herself for the good of someone else. Mariam had no regrets.