Gao Yang is now a command center; he doesn't handle specific matters himself. The only thing he needs to do is issue orders.
To issue orders, he needs to make phone calls, but the calls Gao Yang makes are highly likely to be intercepted for various reasons. First and foremost, many of the people he relies on have identities that are exposed. While he can ensure security on his end, he cannot guarantee the safety of the person he's communicating with.
Back in the day, Chechen warlord Dudayev, after escaping multiple Russian assassination attempts, was finally killed because he used a satellite phone that Russia had access to. After his location was pinpointed, Russia used two air-to-ground missiles to kill Dudayev.
The same happened with Basayev, who was also exposed through mobile phone use and was successfully targeted by Russia.
