He flees into the woods, looking at his watch every moment or so. The girl he loves enters the factory with other workers. She will be killed unless he rescues her. As the factory blows sky-high, he and girl embrace. Allied bombers get through.
Nazis die all over the place.
Then Gene Autry sings Back in the Saddle Again. Then Dick Foran, convict unjustly imprisoned, makes it over the wall. The boy goes home. He has dinner with his parents. His mother's face is bruised.