if you look at the actress's page it says she's playing sonja again in season 4 episode 6.
also i beleive she's the only actress who has been in more than one episode. Playtest was her second episode
I could see it being a 2 parter.
He did send a picture of the technology. It may even be considered illegal, I would have thought that they would have had to undergone riguous testing to even be allowed to test it on humans.
Like to me that is what made the episode slightly less plausable than others, this one did seem to be in a normal world where regulations would exist.
However, maybe they've been getting away with it by not releasing the technology which may like I said be illegal.
Also, she knows that he went there and has the picture to prove it. The main guy in part 1 otherwise would have most likely slipped undetected as he had come on holiday with only Sonja knowing.
Anyway, I quite liked her she could easily be a badass in a part 2 of Playtest. Maybe, she get's caught and we have to see her experience her fears. I actually would like that too. Not as a really long episode but it would be quite cool in future seasons all had a mini playtest senario, maybe like 20mins long max each, showing a different persons fear.
The endless possibilities if done right would be pretty amazing.