They had 20 minutes per the article, in that time frame you would have a traffic jam in the parking lot as everyone tried to leave down the 2 lane road that services the factory.
They had 2 days warning. not 20 minutes.
Comment say that Mayfield had about 2.5 hours of warning based on this blog: https://cliffmass.blogspot.com/2021/12/a-critical-gap-in-tor...
If you look at the area encompassed by the tornado watch, should they have evacuated it in it's entirety? https://blogger.googleusercontent.com/img/a/AVvXsEji0sqQJqWo...
Look about 300mi x 170mi area. If you take Jones burro as the center, its 120mi to the edge, technically if everyone could evacuate at 60mph you could get everyone out in 2 hours.... but with NWS tornado warnings have a False Alarm Rate (FAR) of roughly 70% you probably won't get that many people to evacuate at all unless you make it mandatory. Then it will take much longer than 2 hours to get people out.
You are talking about massive areas with small amounts of time: https://blogger.googleusercontent.com/img/a/AVvXsEhcPxy7gbyr... is roughly 430 square miles for something that is small and fast moving.
I'm talking about not forcing them to come in to work for a 3rd shift overnight run that can most definitely be delayed by a shift for a weather pattern known to create high numbers of tornadoes.