proportions are stretched whenever a wide angle lense is used. gopro is superwide angle. so corners of the picture have very abnormal proportions. learn first, then post.
sorry but this is flat out wrong.
gopro is superwide angle like 10-14mm
every line is like a half circle not a straight beam.
your analysis is incorrect you have to draw in almost circles.
thats another matter and from what I see it indeed seems like the shells disappear. you cant be sure though by the quality of the footage.
it could be a 2 layer footage: one layer street the other layer gun and sheels before green screen.
the horizon line analysis is still wrong though. lense ABERATION is the keyword.