Unfortunately the lift gate latch is electrically operated, and, to my knowledge, there's no (easy) way to open it from inside. Best bet is to use jumper cables to provide power.
Cheers.
The hybrids are able to take advantage of the higher voltage of the hybrid system and battery and this is where they're pulling power from for the inverter. The engine's able to provide a lot of power through the hybrid system. The F-150 hybrid motor/generator (a single motor compared to the dual motors used in eCVTs) is rated for 47hp/35kw. In comparison, trying to do that off the 12v side is going to be a MASSIVE undertaking due to the amount of amps involved. 7200w/12v is 600 amps. The HVB likely has a nonminal voltage of around 300v. That's 7200/300 = just 24 amps. BIG difference.
You must perform the battery capacity test on the Energi to find out how much the battery has degraded. Yes, heat degrades the battery and the battery heats to unhealthy levels just sitting in the summer sun. The Energi does not have an adequate thermal regulatory system to manage safe battery temperature during the warmer months of the year. A search will reveal on how to perform this simple battery capacity test that has to be done in EV now.