Fuses was my first thought too, but I have an update. (Its not the fuse)
I opened the glass, and i was able to pull back the trim panel enough to see the lock assembly. When I hit the button, I could see the actuator tying to push the rod up to release the door, but seemed like it was stuck. A gentle push with my finger pushed it up and released the door. With the dorr open, i was able to remove the screws holding the trim panel and remove it completely.
I removed the entire lock assembly and took apart the lock actuator, which will need to be replaced. Problem is, I cant find a part number for it. Plan on going to the Mercury dealer tomorrow to see if they have the p/n, or what it would cost through them to buy the part.
Here are pics of the actual piece that needs replacing.
http://pics.bbzzdd.com/users/akshatp/lock.JPG
http://pics.bbzzdd.com/users/akshatp/lock1.JPG
Btw.. I alreayd googled "PA6 GF30" thinking that was the p/n, but that turns out to be the type of plastic used on the piece lol.