Dash-cam driver. Slow down after you let the other car in. Secondly, why did you enter lane two when you can see the car in front wants to do the same?
Stupid recovery driver pulls into live lane from standstill. Could easily have used the slip road to build up to a safe joining speed - far far safer. Instead they decide to try creating a pileup.
The circumstanes make it nigh on impossible to pull out safely.