Most cars seem to have a subtle trick to open doors when the battery is dead. Mine (an E90 3-series) has a physical key, but you have to know to pull the lock o

Most cars seem to have a subtle trick to open doors when the battery is dead. Mine (an E90 3-series) has a physical key, but you have to know to pull the lock on the driver's door then turn the key to open it. Turning the key does nothing. Turning the key then pulling the lock does nothing. I found this information buried in the comments of a YouTube video that had elaborate instructions to get underneath the car, and look for some wires in the engine bay to pull so as to pop the bonnet.