Stars like Haruki, Han, and Arisu were protected by insurance that was worth millions. Since they became aspiring trainees, they received a lot of investment from their own families, and then sponsored by the agencies. Because there was hope that they would generate profits and support for dozens of people directly involved in their careers.
This was the common script for most of the fresh faces that drove crowds to theaters and shows. Specialists in the entertainment industry carefully selected the rookies who would make it in the show biz.
They used stuntmen in action scenes that involved minimal risk to the star for this reason. The director's reckless treatment of his stars was more than eccentricness. If it worked, he could be considered a genius. But if any accident happened in his set because of his 'artistic vision', it would be the end of his career. Haruki was worth millions before he even debuted, and Ilan Owens knew it.