Other mistake: The caption onscreen when the C.I.A. Headquarters are shown reads "Langely, Virginia". It should be Langley. [Might be Netflix only].
Other mistake: Twice during the film the words "C.I.A Headquarters." appears in the bottom of the screen. This is a grammatical mistake as the filmmakers forgot the third period/dot after the "A" in "C.I.A."
Other mistake: During the invasion of the safe house, it is noticeable that all the operatives have standard AR's without attachments. This seems highly unlikely as they would have customized their weapons.
Answer: "Surveillance Detection Route." It's what you do when you think you're being followed (drive a specific route to detect if you're under surveillance or not). Weston says "I think I might have picked up a tail", so he was unsure if he was actually being followed or not, but had no time to try and determine if he actually is being tailed or not.
Bishop73