It ain't hard to find, you could do it with your eyes closed. How you'd get there with an Eros oxygen mask on is another matter. With the aircraft depressurised you might be able to open the hatch but whether it helps or not depends on where the smoke's coming from. If it's in the cabin then you've got effectively unlimited smoke to be drawn into the flight deck. Bad times. If it's from the flight deck then I can't imagine there's anything in there that can generate a volume of smoke greater than the volume of air being sucked out of that hatch so it might be beneficial. If all else had failed I'd be inclined to give it a try.