If it can chisel.How do I know if my drill has a roto stop feature?
The setting you have now is for the circular cutter. Turn it left for the box cutter.


Going back to the video in the OP.
A little bit of hunting around on the web suggests that the chasing to install new back-boxes is part of a refurbishment of 80 rooms at a London hotel. Looking at the photos, I'm not sure the installer understands the concept of 'safe zones'. Take a look at the photos on this link.
http://www.sloanepropertymaintenance.co.uk/projects-gallery/sloane-square/