Depth Charge on land

So whilst I was casually viewing one of my favorite shows on the discovery channel, Mythbusters, I got to see the hosts try something that was seen in a movie. Apparently the special was about using different methods to bypass different types of security devices. The last was of course, the safe. The idea that they were testing was to cut a hole into a large safe, fill it with water, and detonate an explosive inside. Supposedly by filling the container to maximum capacity with water and providing an extra boost of pressure, the resulting outward force would be enough to tear off the front door to the safe. Basically, they were going to set off a pressure charge inside a safe. Now although this theoretically would make sense, several flaws were found in this design. One problem was that the safe was not entirely water proof, so trying to fill it up provided some problems. The other problem was the concept itself. What happens when the charge explodes is that the energy from the explosion is transfered in all direction with little to no reduction in force. In other words, the explosion would not be focused enough to simply blast the door off, but would also blow up the entire safe. So everything was prepared and sure enough, when the charge was ignited, the safe fell apart. The door had been ripped off its hinges, but the roof of the safe had also been torn apart and most of the treasure that would have been the prize of any thief was either soggy or blown up.