Well it wasn't a four way stop, we were inside a parking structure, and I had the stop sign. We both reached the intersection at the same time. And both stopped because thats how crappy the layout of the structure is. He waved me through, so i assumed it was safe to proceed, but he's foolish enough to move before i even clear the intersection. Now that i think about it he might have been making a left as well considering the angle of his car.