The guns are only incidental, though of course they're vitally necessary when she goes into action.
We feel this is vitally necessary for the legal protection of each of them.
Now Heinlein does something that is vitally necessary to good writing: he perceives people.
He was always eager to forgive, and the money was vitally necessary.
Never mind that it was vitally necessary and they had more than enough cause to act.
This flight will be full of mundane tasks that are vitally necessary to the space station project.
But, for some strange reason, he felt it vitally necessary that the wooden Indian be concealed.
She regretted having told him now, but at the time it had been vitally necessary to speak to somebody.
That is exactly what Europe needs, as with a lot of other things which are vitally necessary in internal and legal affairs.
And so of the other vitally necessary things.