[elhigh]

^^
It can be damned hard but not impossible to get that door panel off from the inside without opening the door. I think there's a hidden screw or two under the armrest on the door and at least one more in the latch pull. My recommendation is that you leave the window up, remove the door panel and go at the mechanism that way, laid bare. It's possibly slower than going after the mechanism through the window slot, but you're going to need to pull the panel anyway, to set things right.