"Well, you did say that I could come and go as I please."

If Runyu didn't want a demonic cultivator stray that came and went as he wanted then he should say so. Otherwise, Mingye would come and go as he pleased. Use the shadows to his advantage. He does, however, give him a bit of a smirk.

"I'll try to make sure to use the front door when I slip in too. Otherwise, you might have to leave the windows open," he teases.