Broken Link - S4-E26
Revealing mistake: During the fight between Garak and Worf near the end of the episode, a Jefferies tube door is knocked out of its frame to reveal the end of the set - a dark room with a wooden scaffold and various other pieces of equipment (slow-mo helpful but not required). (00:36:00)
Revealing mistake: As Kurn is chastising Worf in the infirmary, the actor's prosthetic nose has become detached from the rest of the Klingon make up. You can see the nose wobbling around as he talks.
Revealing mistake: As Sisko and Omet'iklan are arguing in the Mess Hall, the dead Jem'Hadar solider can be seen breathing. His chest is seen moving up and down. (00:30:35)
Revealing mistake: When the Lakota opens fire on the Defiant, steam begins pouring into the Defiant bridge. The device releasing the steam is visible.
The Way of the Warrior (2) - S4-E2
Revealing mistake: During the fight in Ops, the laws of physics takes a slight dive. While Worf is fighting the Klingons, he hits them with his Bat'leth or his mek'leth, and a second later they react to the hit.
Revealing mistake: Lt. Commander Eddington is wearing the rank insignia of a junior grade lieutenant.
Answer: Worf: Curzon's name is an honored one among my people. Dax: (in Klingon) Yeah, but I'm a lot better looking than he was.
Sierra1 ★