Not only are the trajectory of the rock and the freefalling friend similar, In the film the rock and the skydiver appear to be travelling at a similar speed. While there are a lot of factors in determining meteoroid speed, ones large enough to make it to the ground travel at around 250 meters per second. A freefalling skydiver (i.e. the friend following the rock) travels at only 55 meters per second. That's a BIG gap in speed..