There are so many things to deal with, and Gao Guang really didn't want to drop everything to become some sort of training partner.
Frank was still in prison, Gao Guang wanted to go get him back; Mike's issue hadn't been resolved, and he was worried about leaving him to handle it alone.
In short, there were too many things to deal with, yet once at the Phantom Brigade's training center, not even a phone call was allowed. Gao Guang couldn't remotely give instructions over the phone, which felt utterly ridiculous.
But military orders were absolute, and even if they didn't directly concern Gao Guang, Lloyd, even retired, couldn't ignore them.
Out of respect for Lloyd, Gao Guang had no choice but to comply.
He called together everyone who could move for a meeting; those who couldn't were lying in the hospital anyway, so it didn't concern them.