I'd Do Anything For Love (But I Won't Do That) - Meat Loaf

Assignment:

The principle of substitution says that a consumer is willing to give up some of one good to get more of another good. This principle is implicit in indifference curve analysis since the indifference curve represents this trade-off of one good for another. One violation of this principle is lexicographic preferences. A person having lexicographic preferences will always prefer to have more of good x - so much so that she will be unwilling to trade for a different bundle with slightly less x but a lot more y. Is MeatLoaf saying he has a lexicographic preference against "that"? Suppose that he is unwilling to do "that" - what does that imply for the marginal rate of substitution of love for "that"?