1994 Ford Thunderbird door latch

Actually, each handle is connected to a different release. If both handles are not working, I would think your latch has to be jammed some how.
I would try to get the door pad off, I think it might be possible to do it with the door closed. Make sure your window is up, otherwise you will never be able to get to the latch.

To remove the door panel, pop out the light on the bottom corner and remove the screw. Now remove the window and door switch panel (it pops straight out), I am not sure you can get it out while the door is closed though. Under that panel there is a screw with a ground wire connected to it, remove it. Now pull the door pad straight up (be careful with the wires from the power window panel).

I would try to slide the door pad straight back into the back seat (assuming you can get it off). You will have to remove the sound insulation.
Now look inside the door at the latch, you can follow the rod down from the exterior handle to where it connects to a release latch.
Mine was broken at the plastic clip, if it is broken and not connected, push the latch down and the door should open. If it is connected and functioning correctly, I do not know what to tell you. You should be able to mess with the latch and get it release but I am not sure.

Ryan