The man I recently bought a new 240 from clearly hadn't carried rear passengers for years. Both rear doors were stuck from lack of use. I have freed off the locks on one, but the other defeats me.
The outside handle moves and doesn't feel broken, but nothing happens at the latch. Likewise the interior slide handle. The push button is frozen in the down position, and won't budge either electricalloy or manually.

I have tried squirting in lots of penetrating oil, and also tried operating both handles at once, shoving the door hard, etc, but the latch doesn't show the slightest sign of releasing.

How do I open it, other than by destroying the door card to get access to the mechanism?