Warning: This article contains spoilers for Wheel of Time episode 6.
Amazon's The Wheel of Time episode 6 saw Moiraine swear to exile on the Oath Rod - but she didn't swear what most viewers think she did. Amazon's Wheel of Time is based on Robert Jordan's fantasy books, telling the story of the Dragon Reborn, the reincarnated being destined to defeat the Dark One in the Last Battle. It's a loose adaptation, of course; the plot has been accelerated to increase the story's momentum, and already it's diving into the politics of Wheel of Time's Aes Sedai.
Wheel of Time episode 5 saw Moiraine Sedai return to the White Tower at Tar Valon. It had been years since she was last there, and Moiraine realized her secret lover Siuan Sanche - the Amyrlin Seat, elected ruler of the Aes Sedai - was vulnerable. Facing the possibility she would be stranded at the White Tower, her actions restricted, Moiraine conspired with Siuan Sanche to ensure she was exiled from the tower to continue doing their work in secret. She swore an oath on the sacred Oath Rod not to return to Tar Valon until she was summoned by the Amyrlin. As she left, the Aes Sedai turned their backs on her, symbolizing their rejection of Moiraine and that she is henceforth shunned.
While the moment was heartbreaking for Moiraine, there was clear subtext indicating that Moiraine and Siuan were playing a different game, indicated by what Moiraine actually said as she swore on the Oath Rod. An Aes Sedai is sworn to speak no word that is not true, but that doesn't mean it is impossible for them to deceive; rather, they learn how to use words with care and precision. Moiraine's oath is one such example, because when she repeated the vow she subtly reworded it. The assembled Aes Sedai heard Moiraine swear loyalty to the Amyrlin Seat of the Aes Sedai, but in reality, she replaced the title with the name of Siuan Sanche herself.
Siuan Sanche's position as the Amyrlin Seat is in danger, with Liandrin positioning herself to take the throne of the Aes Sedai. Recognizing this fact, Moiraine has secretly sworn an oath of personal loyalty to Siuan Sanche - and, because the oath is binding, it supersedes Moiraine's loyalty to any other Amyrlin. Should Siuan Sanche be deposed, Moiraine will remain loyal to her as an individual, not to her successor or to the Aes Sedai as a group. While being exiled from the White Tower, her home, is a moment of great sadness for Moiraine, her precise wording in swearing the oath ensures that her secret mission for Siuan is intact.
Moiraine's oath can also be read not just as a clever circumvention of the oath, but also as a declaration of love for Siuan Sanche hidden in plain view. The Amyrlin Seat is not meant to show favoritism to any individual Aes Sedai or Ajah, and she and Moiraine would lose all standing and support were their illicit love affair found out. With Moiraine traveling so often, they're only able to catch bits of time together. Moiraine rewording the oath to be about swearing endless devotion to Siuan herself is her way of expressing her love before being exiled.
Loyalty and love are needed. Wheel of Time's version of Liandrin appears to be a combination of two characters from the books - Liandrin herself and another leading member of the Aes Sedai's Red Ajah, Elaida. In the books, Elaida successfully deposes Siuan Sanche, leading to a schism in the Aes Sedai. The Wheel of Time episode 6 is already foreshadowing this, with Moiraine Sedai subtly choosing a side ahead of the coming civil war. Though Liandrin does not know it, Moiraine's oath signifies her opposition to the next Amyrlin Seat, as well as her personal devotion to Siuan Sanche - a statement made quite openly, but in a manner so careful and deliberate none of the Aes Sedai recognized it.
The Wheel of Time releases new episodes Fridays on Amazon Prime Video.