I watched this again.
I think they are standing back from the wall so they can move better vs. setting up in a fixed position. Also, for reasons that escape me at this late hour, I remember crowding your cover is a no-no.
I think these guys are for real. I don't know exactly what the logistics situation is for our friends from the UK but I doubt they would fire that many rounds and jump around to give some Yankee (kidding) journalist a nice bit of footage, particularly given their (the SAS's) general aversion to publicity and spotlight.
Most of the pics I've seen so far of these guys from A-Stan either (a) have their faces partially covered by a Shemagh, (b) are distant, or (c) are from an angle that doesn't show their face.
It probably went "loud" when some journalist/cameraman happened to be there.