Prison Break

We are in the GDR of the 60s in East Berlin. You are unjustly suspected by the Stasi of spying for the West. Since there is no evidence of your innocence, you have to go to prison for an unforeseeable time. But you're very lucky, there were prisoners before you in this prison who were in the same situation as you, who managed to escape. In one hour there is a shift change of the guards. Each guard checks the cells before the start of the shift. So you have exactly 60 minutes to correctly interpret the clues and escape from the prison. As was common then, the prisoners were separated. You are placed in two separate cells.