Say someone who is being voted on by the majority of the group who is civvie decides they want to withdraw, the host might not see they wanted to withdraw and thus day ends and that person who wanted to withdraw dies, instead the group, if it was effective immeditatly, could vote on a different person because their vote is invalid now and a 2nd civvie would die if its not effective immediatly.
Please, before calling it "illogical" say "unexplained"