Stupidity: Since the main people could not delete, or even change their own Facebook accounts; why not contact Facebook support in order for the company to do it for them?
Stupidity: When Bishop is first holding the gun on Gina in the cabin, he stands close enough for her to grab the gun and try to get it off him. A man of his experience would never make that mistake, it's one of the basic rules of controlling someone at gun point: Stand more than an arm's length away.
Stupidity: When the army base gets overrun the girl jumps on a soldier and starts biting his neck. The woman soldier that's with him aims her gun at them but doesn't shoot, knowing full well there's no hope for the man. There is utter carnage going on all around them and instead she tries to help him and gets attacked in the same way. This could be a plot hole as well as the girl in question is the one that holds the key to survival.
Stupidity: The bodyguard takes Michael's pistol from him and later shoots the pistol near Michael's ear, deafening him, then beats him a bit and leaves him on the ground. As the bodyguard is walking away he gives Michael his sidearm back by ejecting the magazine and tossing the gun on Michael's body. He however didn't eject the bullet in the chamber. Michael's gun, a Sig Sauer, doesn't have a magazine disconnect which prevents a gun from firing with a magazine removed. This was a safety feature for police. (01:33:00 - 01:37:00)
Stupidity: Why does a safe house have a skylight? It is a secure building with hardened doors but a window in the roof?