So, it's rare that I can't figure out a problem, but this is just silly.

Went outside to move the MDX today, and the battery is dead. Ok, no big deal. Can jump it. Just have to get inside. Obviously keyless entry won't work. Try the manual lock in the door handle and...nothing. Key slides in fine, there is no corrosion at all. This lock, as far as I know, has never had a problem. It will not turn with the key in the lock. It doesn't feel like it's stuck, it feels like any lock feels when you try to turn it with the wrong key...as if the pins aren't set properly. However obviously the key is the correct key, tried both (?) and wiggled/jiggled it a bunch just to make sure. Nothing.

Does anyone have any idea why this could be? Not aware of any car that would lock you out if the battery is dead. Don't want to waste money on getting someone to pop it open but running out of options. Any ideas? It's a 2005.

Thanks so much in advance.