If it isn't necessary, Boss Yao doesn't want to transform himself into the Dark Giant and have too many people witness him harnessing this power.
It's not crucial if Yao Xiaomu is seen wandering outside; this information isn't really a secret within Era City. But if Yunlang Security possesses this power and it can even be wielded personally by Boss Yao Cheng, then it truly counts as classified.
The people led by Zhang Heyang from the security division aren't suited to know this kind of secret. Unless absolutely necessary, Yao Cheng doesn't want his appearance to be exposed.
