That is cover. A trailer is camouflage. One will keep the projectiles from hitting you, the other won’t. I stated it depends on the circumstance and specifically stated that without cover the smart move is to travel at a high rate of speed perpendicular to the tornado track. I know that’s not for everybody though and certainly what I am saying here is in no way meant to criticize any poor soul caught up in that storm. My heart and my prayers go out to them all. They are fellow Americans in bad times. God bless them.
Trailers never fare well in a tornado. Many places require mobile homes to be anchored to the ground with cables looped around them. They burn pretty good too.
In the places where they have hardpan (sounds pretty wimpy to me, as we have granite underfoot) they could dig down as far as possible, build a concrete vault, and mound dirt up over it.
When I was a kid, my parents told me tornadoes usually travel from Southwest to Northeast, and to stay near the South wall of the basement. Looks like this storm did exactly that.