Rann knew very well that he could only use the law of undoing once. Anymore than that would definitely cripple him, which is why he had to pretend in front of the Supreme.
This is just his own method of self-defense. Rann knew that he wouldn't dare to attack when facing the law of undoing. As long as Rann did not attack, he wouldn't attack either.
The man stared at Rann for awhile before saying: "Relax, I'm not going to attack you."
He took two steps forward, instantly closing the distance between them. Rann suddenly panicked thinking that he would attack shamelessly, but he didn't instead he asked:
"Were you invited by Extreme Academy?"
Rann glared at him suspiciously and still nodded. "Yes I was, why?"
"Because, I don't see why Extreme Academy would choose you and you'll still participate in the trial. There's something fishy going on. Everyone wants to kill you!"
Rann already knew this.
