I've played with Mind many times, the first time that I played with him, with the first kill he had I thought he was hacking, all the time, but nope, he simply isn't, play with him most of the time and you will get used to it, he has a good knowledge of gameplaying, and has a pretty good control of his movements.And there are something called "common spots" which you need to use "common sense" because most of the kills he does he just aims on the common spots, and gets common kills.
For me this demo is his normal gameplay, he has played many mixed and is skilled...
Good luck on this.