It says the subjects are unaware of the experiment. The real hope is that us, the audience, are unaware they actually are. If the subjects really were unaware, the experiment would end pretty quickly and there wouldn't be a show and so obviously, no money to be made. In fact this is quite an insult to the audience to take us for such fools that people really can be gullible and compliant to THAT extent. Sure, to some level we are, but not to that extent. The moment the ambulance wasn't called is the moment I'm sure a vast majority of us would take action. Stop taking people for fools Derren.
Review of Derren Brown: Pushed to the Edge
Derren Brown: Pushed to the Edge
(2016 TV Special)
The show itself is as much a sham as the events in it.
7 March 2018
Warning: Spoilers