Ahhhh... nice! Great find!
Normally, the manual lock cable for the rear deck lid routes behind the driver's side rear fender liner. Accessing this cable means you have to remove the wheel and finder lining. I'm sure you could probably remove the liner with the wheel on the car, but that could get messy. And, unfortunately, many 996 owners keep the key lug in the frunk and find themselves in a pickle if the battery does dead. With the battery dead, they're locked out of the frunk (as you've experienced first hand) and then, to make matters worse, they can't remove the rear wheels to access and remove the fender well liner.... to access the manual lock cable - to access the engine compartment - to jump the car off... and, as you've found out, the fuse box jumper option is an unreliable method of jumping off the car. And get this...if I'm not mistaken, the 996 has lock actuators on both doors. Many 996 owners have been locked out of their cars after long storage and realize that they can't even access the car's interior. They end up having the break the glass. Can you believe that?!
Now you know why many 996 owners go insane! hahaha
