The more I think about it, the more convinced I am by Sun's point against SMS.
In general, he tends to be active and contributes as town, and lately, he's even consistently been among the top posters. By contrast, he's barely posted this game and has had very few reads: even those were forced out of him, came across as obvious and sheeped, and largely went unexplained. In particular, his suspicion of Sun was weak and shifting. First, it was because he was "tunneling Rubik," something he never explained and failed to mention at all in his two subsequent posts on the matter. He then brought up Sun's vote on Ex, which, while annoying, isn't necessarily scummy, nor did he ever explain why it was. Then, in his latest post, he explains his suspicion as follows: "I thought you were acting weird and scummy." In general, he's playing in a way that's completely opposite from his town meta, which I think he has very little ability to fake, and his contributions have been sporadic and weak.
I think I have a pretty solid scum read against SMS at this point, so there's no reason to go for lesser options like Sun, especially when he's started to meaningfully contribute. I know it's not a great look to be shifting my opinions like this, and it'll probably look like I'm just sheeping Sun. But I think this is a good move.
Unvote
Vote: SMS
If we're going to keep Sun alive, as doubtful as that's looking, then we should probably decide on what we want him to do. Immobilize seems like a good choice.