Man, I dunno... Same thing happened to me, and I found that Volvo made the 240 doors extremely resistant to the coathanger trick. Other than having somebody bring the spare key (if that's an option) the only thing I can think of is a coathanger... Forget trying to get between the door and the body, that won't happen. There is (probably) a gap between the rear edge of the lower window weatherstrip and the "shoulder" of the door. Stick you coathanger or slimjim down in there and fish around. Even then it won't be easy- took me more than 20 minutes, and I got lucky. I really hope it's warmer where you are than it is here...

Good luck!