I guess he had realised conflict was brewing, even if he didn't know the Hallows were involved?

Or the Hallows are just an excuse, and he thinks it's time Zhu Hong settled down and had a clutch of snake babies. ;-p

And maybe only the "I want to help, but I can't" bit is meant to have a double meaning? "I want to help you, but I can't tell you this"?

Yes! That works, right?

I can only conclue that Da Qing has decided that a) SW and ZYL are weird about each other because they're into each other (correct), therefore b) if they're being weird right now, it has to be for that reason (wrong). *g*

HEE! Yes.

Since he can't well keep him unconscious for long, he may be trying to frighten him into behaving?

And test his mettle? Shen Wei can't leave Zheng Yi with him if Tan Xiao isn't up for it.

And we don't even know anything about him other than that he seems to be looking for corruption with Minister Gao, but he's just so smug about it.

This!! (And yet, I'm so delighted when Zhao Yunlan converts him into an ally. *g*)