Although I think the ‘sink or swim’ interpretation is the most plausible, and makes the most sense, when I first read the ‘root hog, or die’ expression, the initial image that popped into my head was someone threatening a pig to root for truffles, and find them, or be made into ham, meaning, more or less, “you will be of use to me, one way or the other, pig: one way you can live; one way you can die.”