This may have been answered before, but I can't come up with search keywords that would find it. Active trooper Angus has MSV2, and is inside smoke. He has LoF to reactive trooper Ralph. Angus is not in cover. Angus declares Move and, remaining in the smoke, moves up to touch some scenery which gives him cover from Ralph. Ralph can't react because the smoke blocks his LoF. Angus then declares BS attack, shooting from the point where he is in cover. Ralph shoots back. Can Ralph shoot Angus at the point of his move before he reaches cover? I think yes, but I'm told some people are playing that, because it is Angus' BS attack that gives Ralph the ability to shoot, Ralph has to shoot at the point he is shot from (so Angus would get cover against Ralph's shot).
It's the All At Once rule at work, essentially no different from if the smoke wasn't there at all. However, Angus has to declare a BS Attack "into, through, or out of a Zero Visibility Zone" for Ralph to be able to shoot at a point where the smoke is covering. Should Angus declare his attack so that his LOF doesn't go through the smoke, Ralph won't be able to declare an attack using a LOF that passes through the Zero Visibility Zone. I'm not sure it's come up during N4 yet, but I'm sure it will as smoke is kind of complicated.
That's my interpretation as well. Unfortunately the All At Once rule isn't clearly-worded enough for me to be able to show it to opponents as a definitive answer.
Oof, that's unfortunate. You may be trying to prove that a rule doesn't exist (specifically the rule that would you may only respond using the same LOF), then, which is almost impossible.
Heh, when you put it that way I think you're right, that's exactly the problem I was having. Well, if nothing else if it comes up again, I can point to this thread as the best available evidence :-) It was only once that I had an opponent advance this interpretation, but he said that his meta plays it that way, so it could come up again. I think global TTS is uncovering a lot of these regional variations that in the past would have just gone unnoticed.
