Oh okay. I was slightly confused because there was this one part in "Objectivism..." by Peikoff that said something to the effect of it was okay for a college student to live at home as long as he was studying and his parents weren't sacrificing themselves. So, I wasn't sure how the firemen, etc. would fit into that context because their job is their value, like how the student/child is the parent's value, but the parents shouldn't sacrifice themselves... so the firemen shouldn't either? Maybe I'm confusing contexts or something, I don't know.