How do you get outside in Nazi Zombies

The 1st 3 maps, to get out the maps you need hack but on der riese(4th map) you can get out by opening the pack-a-punch machine and going inside a other player in the right hand side of it, you need juggernaut. get a crawler(zombie blown in half) to try and hit you, then the other player jumps out and you get pushed up and then get the zombie to keep hitting you and you will thrown out of the map and will be able to get under the map also. just look on youtube