"I've told you what you need to do. There's nothing more, I think," Jason said, pausing before cautioning, "Do not provoke the people from the Holy See… at least, not until you're a sorcerer."
Saleen nodded in understanding. After advancing to a grade-7 sorcerer, he would be able to fly freely without any restrictions. Grade-6 mages could fly as well, but the speed at which they could fly and the height above ground which they could levitate were limited. Only when Saleen became a grade-7 mage would he be given more options to flee in case his opponent was too powerful – provided that he himself did not fall prey into his enemy's trap first.
As of right now, Saleen could fly as well, but height and speed-wise, he paled in comparison to Lex, let alone a sorcerer. Jason was simply afraid that Saleen would become too overconfident in his ability to fly and provoke the Holy See on impulse.