Continuity mistake: Jenko and Witten confront a guy creating a commotion in a market. The felon runs past them out to the sidewalk where, somehow, the two cops are waiting and grab him.
Continuity mistake: During the family meal, Jaime takes a bite of food, then immediately in the next shot, both arms are down, and he is talking and not chewing.
Continuity mistake: Jamie runs to a car which has crashed and has a light pole across its roof. The light pole disappears in the closeups as Jamie struggles to free the driver.
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.