The cores of the other arena hoped to overwhelm his mind with data from their law matrix while they remove his hold over his own law matrix. It took less than the time for him to blink an eye to process the new information. He doe not have a weak mind so they failed to overwhelm him.
Next, he had to fight their combined effort to remove him. He can't beat them so he didn't bother to fight them. He dug his mind into his own law matrix and stayed on the defensive. They have the advantage of numbers. Unfortunately for them, he is not some virus or an outsider. He has inside information that granted him access to the law matrix in the first place.
He knows how to manipulate the law matrix thanks to the snippet of the law of order of the sage that he got from their first meeting. Knowledge is power and he has in-depth knowledge of the law matrix of arena 28 so they couldn't purge him. He managed to secure his position in his law matrix. Then he turned on them.