I know this is an older thread, but I ran into this and found a solution in case anyone else needs it.
Bought a wreck for parts, no battery, no key etc...
Need too open the hatch.
Took a battery from my drill (20V) and 2 pieces of scrap wire,
Climb into the back from the cabin, remove the covers from the handles on the hatch and the 4 7mm bolts holding the back panel in place There are other threads on how to remove the handle covers)
grab one of the handle and jerk it away from the hatch, it will take some doing, but eventually it will come loose
The cover will be stuck around the latch so just pull it away from the top so you can see the back side of the hatch.
There will be a 4 plug pin on top, Jump the first 2 pins with your battery and the solenoid will fire, releasing the hatch
Push it up and climb out the hatch, its easier than going back through the door
Hope this helps someone else