Given he can't see the real version of himself in his mindscape. He was able to piece together what type of test this was. It was a test to figure out what his dualistic state of being was. This made it a lot simpler. He has done bad stuff for a good reason. Good stuff for a good reason. And bad stuff for a bad reason. For this to be possible he must be good and evil at the same time. In other words he is yin and yang. After completing this test some of the madness of the multiverse flowed into him and was combine with his existence. This madness gave him greater insight into the duality of yin and yang.

It was now as if yin and yang were some of the simplest concepts in existence. Even in the form of a duality. Vampiric dust could feel a form of transcendence over good and evil. After that his mindscape shifted to the duality of chaos and order. His insight into yin and yang gave him greater insight into this duality. A duality of good and evil usually goes hand in hand with a duality of chaos and some form of order. They usually are what makes up an alignment system based Upon morality. In his mindscape he could see a version of himself that was chaos and a version of himself that was order.

It was different from the previous duality though. This time the versions of him were also in a state of being that is both half's of the previous duality at the exact same time. Because of his insight he now has a feeling that there are consequences if he gives the wrong answer. He is pretty sure he knows the correct answer to this duality. He doesn't do stuff without reason. Though He can be chaotic at times. He doesn't fully care about order or chaos. This would mean his state of being exists either outside this duality or is both half's of the duality at the exact same time. 

More of the madness flowed into vampiric dust. It gave even greater insight into the nature of duality's. It also gave him a feeling of transcendence over the duality of chaos and order. He felt like he now had been filled with the most madness he could contain at the moment. It was currently a weird form of madness. It wasn't actually affecting his sanity. It was affecting his state of being along with his insight into the truth about the nature of the multiverse. Unfortunately though he found himself unable to leave his mindscape at the moment. It was obvious that he had to do all of those duality's. regardless of whether he wanted to or not.

It was just then that someone managed to force him out of his mindscape before it was too late. It was that Yandere version of frisk. She was still in a spiritual form that resembled a human. But she is different from before. She now was giving off a feeling of enlightenment and was now as white as a skeleton.