There was something wrong with how Hillary said it. Struck me as deliberate & forced, as if she knew she shouldn’t go there but decided to anyway.
Like so much of what goes on with Hilliary, she wanted to brag about how much more she knows about national security than Donald (as she so disrespectfully refers to him). It was her saying, "I know stuff that he doesn't and he might push that button just because someone makes him mad and there's very little anyone can do once "that" button is pushed." In other words, pick me, I'm the smart, experienced one in this race. Like Trump said, she has experience but it's all been bad.
I don't have any confidence that even if Iran or some other country launched nukes at us that she would retaliate. She's a coward and really doesn't care about this country or its citizens. She's in it for her own glory, power and wealth. For these reasons, Trump is the better choice.