Whilst i agree the guy was dangerous. I also do not think that you and the person in front should be sitting in the over taking lane... neither of you was overtaking at that point.
If you had both been in the left lane until ready to overtake he would have zoomed by on the right, illigally. But it would have reduced the risk.
Following this car, and it had already performed a very dangerous undertake at over 70MPH previously,. so knew he would do it again, which he does - nearly going into the back of another car, and then cutting up the one in the middle land and heading at over 100MPH into the right hand lane.
Video is from 4K BlackVue and has been cropped thus making it appear closer than I am.
Whilst i agree the guy was dangerous. I also do not think that you and the person in front should be sitting in the over taking lane... neither of you was overtaking at that point.
If you had both been in the left lane until ready to overtake he would have zoomed by on the right, illigally. But it would have reduced the risk.