Wolfgang found an unguarded armored personnel vehicle and decided he was just going to drive that shit through the Berlin Wall.
But before executing Operation Wall Plow, Engels first had to learn how to drive a tank. In the day leading up to the escape, he parked his truck next to some tank drivers and started chatting. "How do you start it? What does that do? What would happen if you drove it right at the wall?" And because the soldiers were starved in the conversation department, they told him.
"OK, that makes sense. Can you show me by driving me through that wall? It's for science."
That night, after one of the guards apparently left the keys in the ignition, Engels stole his escape tank. He picked the spot he thought he could penetrate the easiest and headed right for it. Unfortunately, his foot slipped off the pedal and he ended up rolling rather than plowing. So when he smashed into the wall, he made a hole, but not a tank-sized hole he could drive through.
The situation couldn't have been worse -- his back end was in the East, and his front was in the wall. Engels was like Winnie the Pooh stuck in a honey pot (of danger). Not helping matters was the fact that his tank was enmeshed in barbed wire, which Engels immediately fell into after exiting the tank. Even as he extricated himself from the wire, East German guards shot him in the back. It took his last bit of strength to climb the hood of the car and onto the wall. From there, West Berliners dragged Engels to safety, nursed him back to health, and gave him asylum.
"I've peed on that wall every single day since."