I am not sure this has much bearing on the issue. Who was she waving by? It seems like she stopped when the truck with the agents that got out rolled up. If she was letting fellow agitators go by, that makes sense. It doesn't make sense if she was waving ICE agents by.
Also, She could have backed up a lot more. I've driven a Pilot and it has a not great turning radius, but you can still manage a three point turn in that wide of a road if you use all of it. And also . . . if a car is slowly backing towards you, you can, like, move out of the way. (Like the agent probably should have done. In my after the fact armchair quarterbacking.)