Vans speeding on extreme right lane

In this video, you first see a Nissan Sunny giving way to the vans by moving to the centre lane then going back to the extreme right lane after the vans have passed it. These 2 vans were behind me when we were along Commonwealth Ave West, heading towards the Cross Junction of Farrer Road. After we turned right to Farrer Road, these 2 vans behind my car cut across the shoulder and went straight to the extreme right lane. As it was about 540pm on a normal weekday, there was congested traffic along the whole stretch of Farrer Road before we reached Lornie Road. They were moving along with the traffic until they reached the flyover that connects Farrer Road to Lornie Road. Then they started to drive at 90km/h. The Nissan Sunny in front of them has to actually give way to the 2 vans by switching to the centre lane! How ridiculous is this!!! These 2 vans' speed limit is only 70km/h, a slower vehicle and hence, shouldn't even be on the extreme right lane! And then you see them racing on that lane at 90km/h. Totally absurd and unacceptable!