A lot of blus were also around the exit, doesn't really prove anything.
Yes except all of them were further away from the exit, carefully watching the reds. He seemed to be standing at that distance knowing it would be his effective flamethrower range.
Only because the video is literally 20 seconds long, there is no context as to what happened beforehand.
No, there isn't much context but it can be drawn from details in the video (which is risky in some situations). I'm also surprised that the warden didn't give a kill order first, or at least sound somewhat surprised that all the reds fell for his ''trap'' (this applies only IF this wasn't an mfk)
I'm presuming you mean as in ''following the wardens orders and making sure if anyone makes even the slightest mistake he kills them''.
And again, this was my opinion since there isn't much proof here, I'm only trying to help using what I have at my disposal...
Edit: I just took a look at his profile, joined on August 12th 2018, not enough time to learn the rules, has only 3 friends, everything else is private. Obvious sign he didn't know what he was doing.