You can explain more, but I will still keep the door open to go either way. Because, sometimes people do things that surprise us.
However, unless mates, I find it hard to find his defense of Cal within reason for a town to give someone else. Except Flower, who does it all the time despite it wrecking my nerves.
Well I can't give you a 100% certainty. I don't have one of those. But there are several things to consider here. Number 1 is that Cal can hardly be said to be doing his upmost to survive the lynch. This would imply that there is a degree of resignation to his death, which need not be there at all if he sees one of his scum mates falling on his sword for him. There is enough doubt around the wagon for Cal to capitalise on that, he could definitely make a push for Melkor or Orca and get something going there. Instead he rolls over. This implies that he's prepared to maximise the opportunity of his death, which is to say, he's okay with it because he knows his death makes some players that aren't on his team look bad. Muugen fits that the most.
The next thing to consider is Muugen. As I need not tell you, he is not exactly the type of scum player who would fall on his sword for a scum mate. Muugen plays for himself and wants to make himself look as good as he can, generally speaking. He'll push what he believes he can get away with, but ither than that it's very safe. Combine this with point one, and the thread reaching a consensus of sorts on Cal, and you have a scenario that suggests Muugen is not aligned with Cal. Now sure, maybe they saw someone making this exact argument, and decided to play for that, but then you look nat what they're actually gaining and it's... not much. If we have multiscum, then Muugen doesn't even really get temporary town cred, because you could just argue he is scum on the other team. So it requires them to play for an outcome that is risky for them and doesn't offer much in return. Ergo, not plausible.
A more plausible candidate imo would be Polar Bear, who, when Cal is a main wagon, made a show of getting onto Cal and then voted him as if he was deciding the lynch, which could he argued was an attempt to claw some credit back for him.
Obviously all of this assumes Cal is scum. If he's town then most of this gets thrown out entirely. But that's my reasoning as to why I'm arguing this.