Okay, some explanations about the commentary, but hopefully anyone with better Japanese proficiency may correct me or just give some more insight.

There seems to be a Japanese saying of "壁に耳あり障子に目あり", meaning "the walls have ears, the sliding doors (shouji) have eyes."

Do you see the puns now? "目あり" (meari) → "メアリー" (meari / Mary)

After looking up here and there, I found there's quite a few of Ib gameplay videos and even fanart that makes use of this wordplay as their titles, but that's about it. I thought the game would have this pun as well somewhere, but that doesn't seem to be the case.

But again, feel free to CMIIW