Quantum events may be stochastic (there's still some hope for hidden variables though from what I understand -- either way, as far as the macroscopic world is concerned, it's basically random) but that doesn't mean that somewhere in that randomness a cosmic YOU is deciding anything. It just means it's random. Anything that follows after that is perfectly causal and determined and can be understood in the context of chaos theory.

So in this view consciousness is better explained as an illusion than as the seat of your will. Because you can't really have a will if every interaction that led to your existence can, in principle, be computed forward in time from the big bang. Physicalists see it as a complex emergent phenomenon akin to a run of Conway's Game of Life that started from a random seed.