Corrected entry: In the railway station fight scene, Riley fights Letty and tries to handcuff her. None of Hobbs' team is watching. As we find out later in the film, Riley is on Shaw's team. The fight isn't for the benefit of any other character, the fight between those two characters doesn't take the plot forward - actually arresting someone from her own team is counter productive, and might even piss Shaw off. (00:45:00 - 00:47:55)
Uri Raz
28th Mar 2016
Correction: It is entirely possible that Riley is fighting Letty to a) to continue her charade of being on Hobb's team just in case anyone's watching, b) because she legitimately hates Letty and is using this as an excuse to fight her. or c) because Shaw knows that Letty has become a liability, and outlived her usefulness. We know Shaw isn't above killing subordinates once they have outlived their purpose to him.