This couple, whoever they are, are not just homeowners. They are used to guns. Even your average gun owner does not expect to confront someone where they have to use their gun. They wouldn't be so poised.
These people are comfortable with it. The woman is not freaking at all. In fact, she's almost smug about it. I don't care who you are, if you've never had to draw a weapon on someone, you do not look that calm about it.