Nathan does not like to have either Katie or I on the other side of a closed door to which he is not meant to have access. So he has no qualms about entering a closed-off room if it means finding one of us.
This morning, for example, even though he had mama there to keep him company, he still wanted to see why I was in the bathroom behind a closed door. So he came over and opened it while I was toweling off from a shower. He came in, looked at me, and said "woah, dada!"
I'm not sure what to make of that reaction. Not sure at all. But, in my limited worldview, I'd say it's certainly better than his reaction the morning prior when he walked in on me in the shower, squealed with mock horror, and ran the other direction.
You want real horror, kiddo? Wait until you learn about genetics.