Betrayal
Bai Zemin really did not want to kill the group of soldiers inside the vault as he felt it would be a pity to lose men who certainly had enough courage to fight to the death.
Therefore, he was relieved that Fu Qigang was not a small-minded person and managed to keep at least some logical reasoning in his head. After all, if Bai Zemin wanted it, he could end all of their lives in a second.
Fu Qigang probably also noticed this when he saw how Bai Zemin was fine even after taking so many direct shots so he decided to bet; bet that the person who had opened the vault was a friendly human and not a hostile one or some kind of strange monster.
"It's Bai Zemin." Bai Zemin replied in a deep voice.