I had the exact same issue in heavy weather a few weeks back. It’s really easy to open the door once you know how!
Around the door handle you should see a few small holes in the round metal surround. The small hole directly above the handle is the one you need here. Take a large pin, nail, small screwdriver or anything else that fits in. Poke it in a bit and you’ll feel the resistance, this is the lock. Give it a bit of a push, listen to the pop sound of the lock opening, whistle some appropriate “Mission Impossible” music and triumphantly open the door while your crew look on in wonder.
