[QuestOverload]

Sounds like either the power lock actuator is broken or the lock rods are either stuck or have fallen apart. All are cheap and relatively easy to fix, but as you said, it requires pulling the door panel, which can't be done with the door shut.

If you can't get the door open once, you're Grade A screwed IMO unless you get creative. I'd try pulling the battery off and operating the door manually both with the key and the inside lock button, so at least you won't have the power locks fighting you (can't win that one LOL).

If you get the door open, remove the plug right in the lower-middle of the panel & the 10mm bolt, the 2 color-matched capped screws near the front of the door, and pop the plastic pins loose by prying the bottom LH corner and working up, then roll the window down and pull up on the panel and the panel should pop right out, then you can go from there.
HTH
--QuestOverload
PS: I'd be interested to know how the he!! you get it apart!