What if the guilty party is the one we need to get us home? Should we just risk outing and killing them for the sake of getting it "right" this time?

[he doesn't know if that's what happened, he has no way of knowing who is carrying out the kills—but another siren is dead and that probably isn't coincidental, he thinks.]

I'm not saying we call it quits, I'm saying we use the time we have as a group to find the best solution we can instead of dicking around for a conclusion we've never been able to properly come to.