General Burkhalter says Frau Linkmeyer's husband has been listed as missing for 2 years. However in the earlier episode Casanova Klink (1967), Burkhalter said her husband was missing on the Eastern Front for 3 years.
There is a reflection of production lighting in Klink's monocle.
There is no indication of how Hogan and the gang got Frau Linkmeyer into and out of the tunnel where they held her. There was no indication or discussion of tranquilizing her, so she would have had to climb down and up the tunnel ladder, and, therefore, she would have known she was underground, not in room 412 of some hotel.