I'm having this exact same issue. I was able to get the door panel off from inside the car. You have to unbolt the seat and get it as far backing the rear seats as possible. Be careful not to rip your leather. Then remove all the screws and stuff so you can take the panel off as you would if the door was open. Now pull the bottom of the door card to separate it from the door. Once the bottom is separated, hold it out and hit the bottom upwards to get it off the top clips. Once it's off the top clips pull the door card towards the rear of the car and it should come out. You will break plastic clips holding the door on that are by the dashboard. And you may break the door card itself.
Now that the panel is off remove the airbag(make sure you disconnect the battery first.) You will now need to remove the vapor barrier on the right side of the door. You must heat up the edges to make the gummy black glue separate. Do not just try to pull it off or you will rip the foam vapor barrier. Once it's off and you can get your hand in the door, follow the cable that goes from the outside handle to the latching device. It should have a yellow casing on it. Grab the cable by the latching device send pull. Your Door will pop open.
You will still have problems after you do all this as I haunt figured out what needs to be replaced yet. It is either the cable from the outside handle or the the latching device. I tried spraying all components with white lithium grease and it still happens. One person said that the cable has started to get moisture iinside and it freezes the cable. And another company said the latching device is summed up with debris. The latest attempt I tried was I sprayed everything with pb blaster, I even got the cable off the latching deviceband sprayed it down the sheathing of the cable. I have not opened the door since. It will be best to keep your door panel off and a 10mm socket in your car. Once I nail down the problem ib will let you know, or vice versa.