On the other hand, maybe she regrets joining the Shadow. It's possible that Moridin/SH are really torturing her on a regular basis and making her life a living hell. She wasn't accustomed to this as Lanfear, where she was worshipped under pain of death.

Cyndane might have a composed ivory mask while she's around the other Chosen, but while she's alone she's an absolute wreck. It's possible that she's a lot like Galina and Liandrin, once important, but now wishing for death but not even able to do that. Considering she's a powerful dreamwalker, she flees to TAR for short periods to weep in private, but Moridin finds her after a short time, of course. She's possibly so desperate that she'd even reach out to Rand for help.