In a way, the comment's just as much of a test as seeing if Mike noticed the layout differences, but it's more subconscious. Along with sizing up someone's intellect comes sizing up how much they'll let him push them around. He would say it's friendly teasing, at least if challenged. It doesn't matter to him if it's offensive or not. The only thing that's important is establishing that he knows what he's doing, here. Do you see this? He's got this down!

He's feeling along this part of the wall, for any sign of a doorway under the wallpaper. There is definitely something over there. The acoustics and layout say so.

"Hmm, someone was thoughtful. And spending time in here after the place was abandoned. I'd like to see." By this, he means he'd like to see the candles and get one to light, because they can cover more area if they can see better. He walks over to Mike and peers into the box. He selects a candle after a moment, as if picking the right one is an important decision.