From what I've experienced it seems to be a simple proximity based thing, which I get
Also, I understand there will literally never be a perfect solution outside of an ai which evaluates every single player in the server and then is able to predict the future, so basically impossible
BUT
how about instead a system based on when that player last got shot or was in the general direction of where someone was shooting (IE suppressive fire / missing) system instead, cuz this current system seems to not account for people on different floors, so that screws it up too, I think this will be a better way to do it
And if it turns out my theory on it being based on proximity is wrong I guess this would all be for nothing