Something that people have claimed, that I've always found a tad ridiculous, is that I could be a tracker maquis who prevented mcmc's lynch just for the fun of it. Especially because, if this is true, my partners are Glooble and Munch. And yuma claims that Glooble was the alternative to mcmc at that point. So my reveal would save mcmc at the peril of Glooble, my scumbuddy under this scenario.
Now, as for yuma, I think he may have been trapped in a scenario I found myself in M-VIII... a scenario where you are trying to be voting for your partners, but have them not actually get lynched. I tried to do this in M-VIII, repeatedly voting for my scumbuddy Captain_Frisk, even in the increasing likelihood of him getting lynched. I really did feel it was the only way to disassociate myself from him--have me be voting for him as the town mislynches a town. And it didn't work, I got Frisk lynched, and my other partner, O, was super mad at me. So I think yuma might just have been in that situation, either with mcmc on Day 2, or with Glooble on Day 3.