It's not the firing I'm talking about - it's the sound and sight of an aircraft approaching close enough to get its gun-sights in. Does any aircraft strafe at supersonic speeds? And in your case, were you expecting it/keeping an eye out for it as IS is?
Interesting to note the RAAF aborted a mission a couple of days ago because a target they were tracking in Iraq quickly moved into a civilian area - apparently aware there were aircraft in the vicinity. The Australian chief of defence noted IS had already started changing its tactics in response to recent air strikes.
RAAF fighter aborted air strike on Isis target to avoid killing civilians | Australia news | theguardian.com