7.49 to 8.20 The shining debris should go straight line in space, why some of them go up and down,  some float around?

9.00 What is moving on the bottom of the round glass window on the lower center of the flame? The sun is at the left, why we can see the right side of the ISS and people that are in the shadows? In space there is only one light source, all shadows should be totally dark.