It is fascinating watching.
I reckon the traitors were selected due to having sufficient resilience and "self-deception" to withstand being duplicitous. As in, they are able to persuade themselves it's just a game in order to not crack. There's no way I'd be able to maintain my cover, I'd definitely feel the pressure. So, on that basis I reckon the traitors were selected on the basis of personality tests.
The group nature of it all is fascinating. I like considering the amiability of some people (Meryl, Amanda, Matt etc.) vs those that don't seem so warm and personable (Kay, Nicky etc.) and how much of my judgement is down to my prejudices. Also, the lack of emotional intelligence of Imran who is obviously super intelligent bookwise.
That wheel game - ruthless. Who's the most manipulative, two-faced etc. "Yay! Yay! Yay!".
Also, I feel sorry for Matt, Alex and the producers are stitching him up like a kipper.