Let's do a little myth busting here. An old wives' tale held that you couldn't outrun a tornado, so don't even try -- it would be too dangerous. The tornado would grab your car and shake you out like salt from a salt shaker.
The tornado that hit Newcastle and Moore, Oklahoma, on May 20, 2013, was big, powerful, and dangerous. The destruction in its wake was horrible with lives lost and whole city blocks destroyed. The National Weather Service declared that it was an *EF5 tornado which means the best way to survive would have been to go underground or get out of its way.
The NWS goes on to say that it touched down at 2:45 PM CDT, left a 17 mile path which was 1.3 miles wide, and ended at 3:35 PM CDT. So 17 miles in 50 minutes gives it a traveling speed of slightly over 20 MPH.
Granted, few of us could run a 3 minute mile on foot, even with a tornado on our trail. And someone trapped in a school or other building might be in trouble. But look at some of the video samples here and here. Anyone in an automobile should have been able to get away from it, even those fool hardy storm chasers in that second video. The traffic wasn't that bad.
So anyone wondering whether to hide in the hallway or jump in a car and skedaddle has the answer.
*EF5 means that three-second gusts estimated at the point of damage were over 200 MPH. See Enhanced Fujita scale.