Book 1 – Ch.2 – Pg.17
Elliwiny: Jack has this verbal tic that hints at his internal struggles that we sort of touch on in this scene, and I think we were originally going to like, get into it or make it worse on one of his really bad days, but I think we became less married to that idea over time.
If you are so nervous about being followed, wear glasses. An trick I first saw in Dick Tracy, glue little mirrors to the corners so see what is behind you. A modern version could be spy cams in earrings or hair clips feeding an AR HUD in the lens. But as Jack alludes, most important is body language that does not attract attention :}