I mean you can just filter the milk and extract the water, what worries me is all acuatic life dying which would mess with the oxygen and then the whole wish also messes with the temperature of the earth and would lead to us dying. Without considering the water in our body being turned into milk. Blood is kinda already milk but unfiltered and stuff tho. Anyways, probably either an uncomfortable, painful and slow death, an extremely painful but quick death or an instant but painless death.