Factual error: When they first bring Grueber into Castle, Sara states that "he is one of five people who can hit a target from half a mile away." Half a mile is 880 yards. Basically every person who has graduated from (or likely everyone who has been selected for) sniper school in any military in the world should be able to do this. (00:05:20)Prince Ly Squisher
Factual error: A recurring mechanism in the series is if the power fails the prison cells that are magnetically locked open immediately. No magnetic locks are designed like this. They would fail their initial purpose which is to provide physical security. If a power outage occurs it would take hours before the locks would be released.