Flusha is smart and is using an aimkey in a very specific way to gather information.
https://i.imgur.com/PwS5msu.gif Holding the smoke, knows someone could come out forklift but they haven't yet so he presses his aimkey to see if there is still a T at forklift.
http://gfycat.com/RemoteGrimIchidna They don't have any map control of the sewer area so he prtends to be looking behind but presses aimkey while turning back to know if they are close.
https://gfycat.com/InfatuatedSeriousGalapagoshawk Same as above but he doesn't hide it as well
http://gfycat.com/DesertedDarlingEasternglasslizard More checking for information, this time pronax though
https://gfycat.com/EvenConfusedHellbender Turning around then pressing aimkey while turning back to know if they are close or not
http://gfycat.com/PeacefulAnotherCuckoo Aimkey to check for information yet again
Seriously if you don't see anything wrong with these clips then you're just ignoring it or refusing to believe that a pro player would be cheating at this event. "Surely no one would be cheating after the accusations" everyone is saying, so they keep cheating because no one would expect it.