The first time that Rowan's Reflection entered the Frozen Road and recorded the songs of the Sirens he had always stopped himself from finishing them because he instinctively knew that this would cause devastating consequences in reality, leading to changes he could not anticipate or handle.
At that time the Reflection had no true understanding of the nature of reality outside the universe and could not withstand the consequences if he completed this act.
This instinct that allowed the Reflection to stop his recording was a knowledge that Rowan understood as it had been shared with him by the World Stele but he had purposely held back this knowledge from his Reflection because he knew that if his Reflection understood the consequences, he would simply destroy the books and never place them inside his dimension.
