Thier is a way to open the trunk with out no power but with key. it is very weird to do but their is a secret key cylinder. You have to climb into the backseat and remove them by a little clips when u remove them u will see a key slot u put ur key and turn.
the sound ur hearing is the door lock mechanism it basicly will relock or reunlock thats why u dont hear big click causes it is already in that position it is just moving the lock more to the position it is in. When the fuel pump is priming is when u press the start/stop button, logically speaking if it was priming while fueling that would be a recall it is definitely not fuel pump. The resson why u got amps when the car is unlocked is cause the car was unlocked and the computers were powering up as well.
Also if ur car key battery is out and u need to start it put it in the cup holder this will cause the car to send it a low energy microwave that will power up a low power chip that will talk to the car and say yes its me. but the buttons wont work but it is a emergency power up it doesnt charge or anything