As the date of the escape attempt drew closer, the Mounties and military guards moved in and seized the prisoners as they sought to implement their plan and collapsed the tunnel.

In desperation, one of the Kriegsmarine officers, Wolfgang Heyda, captain of U-434, managed to escape over the camp walls using a crude zip-wire on electrical cables.

Heyda eluded search parties and the massive police response and somehow made his way on Canadian National Railways passenger trains from southern Ontario to Pointe de Maisonnette.

Heyda arrived at the location at the appointed time only to be arrested by Mounties and naval personnel, who were waiting to co-ordinate a surface task force that would attempt to attack and/or seize the U-boat.

In the book, Operation Kiebitz (which is referred to by name) is meant to liberate thirty German submariners rather than four, but their tunnel prematurely collapses, so only three men make it to the rendezvous point.

In the book, it is hoped that their contributions might help Germany sue for peace on better terms, while in the film, the plan's leader seems to arrogantly believe that they can change the scope of the war.