The below link from CNN interview with the man who made the videotape. He said all that was left standing was the freezer they were in and even at that there were holes ripped into the freezer.
http://cnn.com/video/?/video/bestoftv/2011/05/23/exp.am.joplin.convenience.tornado.cnn
A link from Isaac's twitter
http://isaacduncan.bandcamp.com/
He is a musician and a very lucky young man. From the video I could hear him and his friend saying that they loved everyone as the tornado hit and they thought they where going to all die. What a wonderful young man to care about others in catastrophe.
Listen to his song it is very touching.