Considering Alyssa has directly threatened Jesse as well as getting in his way there's nothing she can do or say to calm either of them down in my opinion. The Dark is too strong in Jesse at the moment for her to appeal to his humanity. He's simply not interested in anything she has to say right now.<br/><br/>The best way to defuse the situation in my opinion would be for the prophet to blab, because that would make the Dark lose interest in the prophet. If he isn't interesting to the Dark, then Jesse has no interest in the situation either. Alyssa would still have to deal with the consequences of interfering as the Dark sees it though.