Where was the rifle?
The resolution is just not good enough to consistently show the long object. It is probably too thin to consistenly be picked up in the camera pixels in every frame. It shows up consistently as you watch the video as he runs across the roof. It works better to slow the video down.
Ummm...I’ve watched several versions of the vid, several speeds/magnifications ... I don’t see what can possibly be a rifle, in whatever he picks up.