It's nice to see someone citing their source, CableRunner - lol!
Desmond can keep saving a man's life (which I am sure Penny would want him to do) but would keep him from Penelope, (remember she tells him he's a good man); or he can not save his life, and by doing something shameful, keep the picture on the puzzle box (see promo for next week) the same and be with Penelope, but run the risk of making her ashamed of him.

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`Dear, dear! How queer everything is to-day! And yesterday things went on just as usual. I wonder if I've been changed in the night? Let me think: was I the same when I got up this morning? I almost think I can remember feeling a little different. But if I'm not the same, the next question is, Who in the world am I? Ah, that's the great puzzle!'

-- Alice, from “Alice’s Adventure’s in Wonderland”