Its not that the cops are going to shoot you as you're slowey laying your gun on the ground, it is that your plan to do so against their orders dramatically raises the odds that they might. And... All together now in harmony, the threads is about not getting shot. And the shooting will likely happen relatively soon in your movement cycle as the fact that you are (a) moving and (b) moving the gun register as they are hard front-sight focused on your COM.
But hey, it is a free country. You don't have to agree with or take the advise. The odds of your having to follow it, regardless, are low.
Meriam Webster's: Main Entry: ci·vil·ian Pronunciation: \sə-ˈvil-yən also -ˈvi-yən\, Function: noun, Date: 14th century, 1: a specialist in Roman or modern civil law, 2 a: one not on active duty in the armed services or not on a police or firefighting force b: outsider 1, — civilian adjective