Actually, if you look closely, you can see right after he kills that guy at 1:38 his cursor pops (like aimbots do) towards the guy who is behind the wall (who you see comes out right after the pop happens). Happens again from 1:45 through 1:48. Just look closely, you'll see it too. His gun bounces from one person to the next, even when the person isn't visible.
And yes, I know this is a hacking website, but don't claim to be legit, when you're clearly not.