Hoe do I unlock my rear hatch door with a dead battery?

I'm not positive about this but most vehicles that have a battery in a hard to get to spot have a jump start terminal under the hood. There may be a red plastic cap with a "+" sign on it. It hay even say "Positive" on it. Pop the hood and see if you can find it. The owners manual, if you still have one, will have the location in it under "How to jump start your vehicle". Hope this helps.