he knows if he wanted to extract some memories from his Mind palace that is a very hard task.
Sometimes, it would take time.
Sometimes, there is a risk of memories overlapping with each other and affecting each other
This is the corruption of magic.
Magic knowledge is not like mortal knowledge.
If you read a book and manage to memorize it, and if you are someone who had a great memory then you could always remember it later.
Even when you are old, while some of them are something you have already forgotten, you would still remember some of it.
It is even more if its something that is drilled into your body like some kind of muscle memory
But magical methods are different.
The moment you learned it, especially the high level magic, the longer you hold such magical method in your mind, there is even a chance that the magic could corrupt your mind or overlapped your memory unconsciously.
No pain, no hardship, unlike his experience in the past.
