Houdini Blackjack

Seems like we're going to have to deadbolt the door when we leave in the future.  We were just out for less than 2 hours and as we walked home from the tram, someone that works in the apartment office passed by and told us that our dog was running around on the stairs.  After hurrying back home with visions of Blackjack escaping from the common area stairs out into traffic, we found that the landlord had just finished replacing Blackjack in our apartment and deadbolting the door for us.  Hopefully Blackjack wasn't out too long...I guess it's either the crate for him when we leave or deadbolting the front door.  The only problem with using the crate is that I took the door off and I've wedged the door into a corner and tied the potted palm to it (I don't know where to buy the more common stakes that would support the palm). I'm pretty sure Blackjack won't be able figure out how to turn the little knob for the deadbolt.  Then again, I didn't think he'd figure out that he can stand up and push the door latch down and then pull it towards him to open the door.  He doesn't do this when we're around - if he gets left out when someone remembers to shut the doors to keep the heat in the room, he'll just paw the door politely and wait for us to come open it.  Oh well, I'm just glad he didn't run out of the building when some unsuspecting tenant opened the outside door.