![Blue Bloods mistake picture](/images/screenshots/309000-309999/309965_sm.jpg)
Continuity mistake: While Danny and Baez are questioning Damian about Mason's whereabouts, Damian's right handcuff switches to the opposite way depending on the angle of the shots. Either the single metal bar faces up or the double bar faces up, which is quite impossible to change when it's locked around his wrist.
Answer: It's a common cop show plot device. If the police on the show always acted in the most logical way (i.e. not alerting a suspect to their presence) the show wouldn't have the opportunity for an exciting foot chase.