Continuity: Although Herr Flick and Herr von Smallhausen have their glasses smashed on the floor in the previous episode, if you look close they have apparently picked up the broken glasses and are now using them. You can see one lens in Herr Flick's glasses is missing in the other is cracked. It has been previously reported this was a continuity mistake, but there is no continuity mistake here since the glasses are shown as being broken.
This episode is the last one Captain Hans Geering appears in since being spirited away to England by the resistance in Season 4.
The final Appearance of Sam Kelly as Captain Hans Geering, Kelly was more than eager to return to the role having regretted leaving the role when he did.