I went looking for a box this morning while Kalena was watching a movie. It wasn't in the first couple places I looked, so I decided to check out back in the shed. After some maneuvering (our shed is currently completely disorganized) I found the one I was looking for and turned around to bring it in the house. Just in time to watch Kalena shut and lock the sliding door I'd left open.
After making sure our side door was also locked (it was) I called Brian. While we waited for him I tried to get Kalena to unlock the sliding door. Unfortunately, it is considerably harder to unlock than to lock, and Kalena doesn't have the required level of coordination yet. Fortunately, Brian's office is less than 10 minutes away so the wait wasn't long. Also, VERY fortunately, Will was napping at the time which saved me a considerable amount of worry.
Kalena was unfazed by the whole thing, although she did seem a little confused about why I wouldn't just open the door. She kept asking, "Play outside? Open door?" and then she'd try the door and say, "Door locked." like it was my fault. In the future I'll be checking the other doors before I rummage around in the shed. Glad I got to learn that lesson on a nice day like today.