Unless someone possessed a very stable will, they would lose themselves without even noticing what had happened.
But in this case, losing oneself wasn't a bad thing. When people were uncertain of which path they wanted to traverse in their life, they could lose themselves in the drawing and choose a mind to complete their purpose. For people who were still establishing their own identity, finding a mind within the drawing that they could claim as their own could help them in the future.
Han Sen was different. He already had a path to walk, and if he allowed himself to be influenced by the mind of the drawing, the core of who he was would be destroyed.
Han Sen forced himself to close his eyes and escape the grasp of that mind, but all sorts of minds rose against him, trying to keep his vision fixed on the drawing.
Fortunately, Han Sen had a very stable will. He was able to tear his gaze away from the wall. He slowly soothed his mind.
