Try to imagine a solid block of ocean hundreds of miles long, 3 miles deep, and as wide as the coastline, coming toward you at 500 to 600 miles an hour.  That describes a tsunami in deep water racing toward land.  A tsunami’s speed slows as it encounters the coastline but the total water mass is still moving at 20 to 25 mph just before surging ashore.  Maybe a world class distance runner who runs a 4- minute mile can stay ahead of an oncoming tsunami, but most of us are not world class runners.  If it comes down to a race, the tsunami will win and the runner will lose almost every time.  A tsunami rolling onshore is massive, powerful, and destroys everything in its path.