When Professor Leon told them that it may be a person "out of the ordinary", Frey and Angeal already understood what he meant.
With the two of them being involved with immortal beings and with Professor Leon knowing this information, he may think that this Dylan could be that kind of person.
"After telling you that he would go to the comfort room, he did not come back," Professor Leon said, popping a piece of chicken in his mouth. "So, it would mean that he indeed went away. He did not even have his things inside the room, right?"
"Yes," Angeal answered, nodding at the same time. "If that's what you think, do you think he would come to class tomorrow as well?"
"That we have to wait," Professor Leon said, letting out a small sigh afterward. "We would have to follow the school's protocol if he were to come to my class unenrolled. And if he continues this shenanigan, I would have to report to the security."