Jim threatens Melinda's father that he will kill him if he doesn't tell him the truth.
-But Jim, you have sworn to save lives.
-Comes out a roaring second

compared to saving my wife.
What does the underlined mean?
In a contest or race, his vow to save lives in general loses, and saving his wife is first. I haven't heard "roaring second" before, but I would guess "roaring" means "giving it everything you have, making a strenuous effort." So, although "saving lives" is a strong contender and runs a good race, it still can't beat saving the wife.
Rather a complicated idea for so few words!
Thanks, Delmobile.