>> the zip dips but it doesn't tip. >> instead of going over like i knew it was supposed to, it fell into this hole. a story and a half was blown out of it and there was really only one metal pipe that broke off. otherwise, the entire structure stood. had the contractor said, what's going on? we said, we don't know. we're not sure why it didn't go down. it may still fall. so we've got to be real careful. >> so why did the building tip but not topple? when the blast knocks out the lower floor, the remaining floors rush down and crush a foundation softened by years of standing water. once in the hole, the zip just sticks. >> this has been great because it says, i'm not going down without a fight. >> there was a 15-foot deep basement under the structure that was actually blasted into