[redhed]

The battery is under the rear passenger seat, actually. Try doing the key trick on the driver's door, and then manually unlocking the passenger door from the inside, maybe?
Also, even though your seats don't fold, there might be an access through the armrest thing in the back seat. Many of them lead directly to the trunk, if you can find a kid small enough to climb through it and unlock the door for you. (Don't laugh...it's been done)