The crocodile makes a small arcane gesture behind his back in order to cast a spell. Tyamet's mental defenses were never actually as great as she thought they were and the crocodile’s compliments only made it worse. But a small part of her subconscious mind realized that a charm spell had entered her mind. She knew that if she didn't stop the spell she would end up eagerly and happily doing whatever the crocodile wants. The spell was already wrapping itself around her brain, rewriting her mental processes as it progressed. Her altered mind told her that it would be wonderful to do whatever Pierre Le Fuud wants.
The subconscious part of Tyamet's mind knew that it had to resist the charm spell before it completed altering her brain. If it finished, then every part of her mind, conscious and subconscious, would desire nothing more that to please Pierre Le Fuud in any way he sees fit. The only way to stop a charm spell is to resist it until the spell loses power. If she can do that, her mind will be her own once more. To resist the spell, her subconscious mind has to think about anything except what the charm spell want her to think about.
