This is what morda says: "You should've waited till 1 irl day later to say this for if someone else wanted to claim because now you have a target on your back for NK." See the bolded; why would someone (Nick) who is convinced they protected someone else from the kill (morda) first off wait, but specifically wait so that others could claim? Why would there be other people that might claim?? Where does morda get that idea from? At that point, Nick was emphatic that he stopped the kill, and there was no reason to doubt that. But if morda knew that someone else was the person nightkilled (i.e. because he is scum), and that there was another way for the nightkill to be prevented, then you can see what caused morda to get the idea that there could be others. The only other explanations for this would be Morda is in a mason chat with Roz, or scanned Roz, and knew that there was others (although this doesn't explain why Morda doubted Nick's story straight up).