'Launching' D3 4.2tdi

[jonnypym123]

Something that's puzzled me when I'm driving to work , waiting to come out of a junction/roundabout is how the power cuts on the D3 4.2tdi when holding the brake pedal and building the revs as you would use a clutch on a manual ready to move, (I know this isn't its's intended purpose) the D3 A8 3.0tdi I was able to build a decent amount of revs to launch the A8 however the D3 4.2tdi does seem to want to play

This guy in the video seems top have it sussed, do you reckon he has it held in P build revs and drops into S or am I missing a trick?

https://www.youtube.com/watch?v=MuUMeNzG60M&t=1s