How do I get the trunk open when the release mechanism fails?

I have tried the button on the fob, the release switch inside car, and the metal key hidden inside fob. I have even tried to access trunk through back seat. I hear it is some strange pneumatic release mechanism. It used to work just fine. I can't get to a dealer, nearest is 4 hours away. A local mechanic wanted to cut through the metal behind the license plate. I only NEED to get in since my tail light bulbs are starting to burn out. Any suggestions?

Would there be a cable if it is pneumatic? I had the local mechanic try to get through the back seat. For some reason he gave up on that idea.