There are too many imponderables: you are, to a certain degree, expendable.

I know you hate to burn up a ship, but this one is supposed to be expendable.

If we're caught, who knows better than we that we're expendable?

Hoskins goes, because of all of us, the Engineer is most expendable.

In attempting to avert that tragedy I'm expendable, as is everyone else here.

A commonplace: why go on worrying at it, insisting that no one is expendable?

Maybe he can get some of our men back to Earth, though of course we're all expendable.

In attempting to avert that tragedy I'm expendable as is everyone else here.

We reject any insinuation that one race or another, one people or another, is in any sense inferior or expendable.

That's why I told Space Patrol to send me a brand-new second lieutenant—young, strong, fairly handsome—and expendable.