While performing his little trick, there was always a worry in the back of Raze's mind. He knew that it might be seen through by Barlan. From the information he knew, Barlan was a 4-star mage.
Knowing this, Raze had drawn the memory loss formation using a circle that only a 6-star mage would know. On top of that, he hid the real magic circle formation of the light show that was activated by his lightning magic.
Doing so, he wanted to make it seem like it was magic, and using a formation that Barlan might not understand. It was possible that Barlan would have asked questions while he was doing his work, raising the suspicions of Marcus and the rest of the group, yet he did not.
Which was why he thought he had gotten away with it, until this point right now.
I am driving and on a flight so chapters might be a little strange on timing wise the next few days