Luna as a prisoner in a gulag, was restrained in an isolation cell on her first day. That was to humiliate her and show her that she has no rights any more. No rights for clothing, no right of freedom and no choice.
While serving as a personal slave, Luna experienced another torture method. She was restrained with her ankles and wrists together on a spreader and tortured with fire. Her master finished this session with some extra spanking.
Luna was taken to an abandoned building, where she was undressed and restrained, then left there while her master was gettiing ready to play with her. In such a remote setting, he will play with her for a long time.