Is lying a milestone?

Well, as some of you may have heard, J has defeated doorknob locks. So, for those who are wondering: don't get this kind, with the hole in the front. Little fingers can grip the doorknob that way.

Anyway, we've been dealing with J's new obsession with opening all the doors previously forbidden to him (the front door now has a chain lock, for the record). He opens the bathroom door; he closes the bathroom door. He opens the master bedroom door; he closes the master bedroom door. Usually.
I was playing with B in the living room while J played in his room, or so I thought. I then heard the bath being filled with water, so I decided it may be prudent to go check on the boy. As I rounded the corner into the bathroom, J was, as expected, removing his clothes.
"I take a baff."
"No, it's not bath time."
"Baff!"
"No, bath time is after supper. Come on."
"No supper. Baff!"
"No, it's not bath time. Let's put your clothes back on."

I succeeded in convincing him that he did indeed want supper (pasta is pretty popular around here), and escorted him out of the bathroom. Surprisingly, B, despite her new-found skill in crawling, stayed in the living room.
"Okay, I'll go make supper. Can you close the door?"
"No close a door!"
"Close the door."
"No close it!"
"J, we can't let Baby get in here. The door needs to stay closed."
And here comes the kicker:

"Baby says door stay open!"