Revealing mistake: Season 5, episode 18 "Point of No Return": When Danny fires at the bad guy, there are sparks coming from the metal pipes when his bullets hit them. One of the things causing the sparks burns too slowly, taking over a second before it fades out.
Audio problem: Season 5, episode 18 "Point of No Return": When Hawkes is talking to Mac about the fibers he found, there's a brief shot of his silhouette in which his lips don't move while talking.
Chosen answer: Probably to broaden the scope of the show's plot and give the audience a chance to see the characters in a different setting, People act differently at home from the way they do at their workplace. By the ninth season, the characters would have become overly familiar and predictable. It gives the writers a chance to do something different with them.
raywest ★