I like how they went about structuring things in order to keep it vaguely plausible that they can keep the family hostage for 2 whole weeks, and I'm really intrigued by McDermott's character and his motives which he says are his own, I didn't get the impression he was being coerced into the plan.
I'm pretty sure Angela is still alive but the fact that neither the black guy or the girl knew what the plan was going in, and are seemingly hired guns, didn't sit right, you don't find out you're in on a plot to kill the most powerful man in the world and just shrug it off.