There’s a string stating that the code should not be passed or the employee will be fired. I’d assume this was a test to see if an employee meant to be doing code review was actually doing them. Spoiler, they were not, as OP said they found this in production code.
I’d go a step further and I suspect it’s a peppering string (i.e. fixed string you add to hashes to defeat rainbow tables). I’d really hope it isn’t as you mentioned because gosh that sounds like a toxic workplace if someone is just leaving landmines around purely to get someone fired.
More like, you know damn well that Jim keeps passing code reviews without reading a line in them, he’s been talked to, still does it, and you need something actionable to prove it so that you can get someone’s ass in his chair who does their job.