on the little nylon screws, you should turn it with no pressure apply, and it should come out, last resort would be pry them out. But you are risking at the point of pontential need some new ones.
As most people on Prime recommend: Do not take the taillight apart in attempt of getting rid of moisture. the plastic is too brittle to pry apart. With about couple inches deep of water condensed in my light and it dry off ever since, rest assure that it will go away provide that you have good seal.
Procedure.
open trunk, pull out the rubber trim. (You may left the other half in place.)
Take off all the nylon screws at the back, you might have to pull couple back on the side. Depending on how your CD changer is mounted, you might have to take the bracket out to pull the pass. side one out.
use pryer to remove the wiring clips that's hold on to the tail light's bolts.
then start removing bolts... You do need a deep 8mm socket. Starting by the 4 in the middle, your center lens should come right out. There's like 3 bolts at the triangle end of the tail lens... and 5 or 6 more on one side of the tail lights, You will see them.
When all nuts been remover, start pushing from the triangle end, then move to the middle, yes you need to force it a little, the gasket is very tight. If you want to wait until the 4th, I'll gladly show you all it's needed in person.
PS. If you middle one is leaking, we might set up a date to fix it. Since Polar's and Freelance's both had water zipping in. We are planning to do it someday.