Diara mentioned the tower having its sentient, so they could not relinquish authority over it to Kyran just like that. The tower would first have to recognize him to be granted full authority over its activities and mechanics.
When Kyran confessed that his magic underwent a significant transformation within the tower's confines, Shaiha was genuinely shocked. It meant that the tower had a profound effect on his magic.
The effect did not happen right away. Shaiha could attest to that because she served as the central core of Kyran's four magic cores. Her role allowed her to perceive instinctively how powerful his magic attacks would be.
