Continuity mistake: As Tris is doing her first fight session, she dodges her opponent's hit and the majority of her hair is shown going over her shoulders. In the next shot, it's now only a few hair strands over her shoulder whilst the rest of her hair is resting along her back. (00:36:00)
Continuity mistake: When Tris is on the zip line, after she does her flying impression and passes by a building, the shot returns a close-up of Tris where there are strands of hair being blown across her face. Next shot, her face is free of any hair strands. (01:01:30)
Answer: There aren't really obstacles. On a zip wire, there isn't really much scope for manoeuvrability. You follow the wire.