Confirm that the seatbelt buckle is not wedged in the door from the inside. This is a too-common event. If the buckle is indeed wedged, start off by trying to pull the buckle out from the inside. You may need to fold the seatback down to get a good angle to pull. Get creative if you need to.
If that doesn't work, the next option is to push hard on the outside of the door immediately adjacent to the latch area, hard enough to unload the latch and allow the door to open. Don't dent or bend the door edge; go back a couple inches from the door edge and press firmly with your hip if you can, while applying gentle pressure on the outside door handle to open it. There is no disassembly alternative to this method; the door cannot be removed from the closed position.
You will need to remove the screws under the indoor handle and below the armrest (just look up any video on Pilot door disassembly)
Pry up and unplug the piece that has the window up/down button.
You then need to pry out the top of the door panel. Not going to be easy with door closed, but that is really the only way. Once you bend inner panel away from the door a bit, you might be able to get to the lock.