I'm not entirely sure I can abide by that. Plus, again, we don't know if Millie is just suffering from a mental disorder OR if her case is unique amongst the Stalkers-it would probably take confirming another Stalker to really pin down what's going on.

Plus, I feel like you're forgetting that we don't know if the Sin Purge ritual actually relieves them of these theoretical 'parasites' or just kills the hosts and symbiotes together. And while I'd hate to be that guy, it's really more like Demonic Possesion than something parasitic.

Most pragmatically of all...We don't know the whole ritual, aside from not knowing what it does in the first place, and we aren't exactly on the fast track on that. I say that we ought to be ruthless and save what we can, and if we can't, bid them a merry sigh off to Utopia-and our hopes that they were merely victims of this tragedy instead of the actual villains (or that the villains don't drag them down). I presume that failure is the most likely option, not the least-success isn't guaranteed and we ought to secure every step. We can purge who still stands if we get the ritual up-but we have to act as if the other Stalkers are going to be much harder to find and pin down.

And again, we don't know if they're just insane or were hiding a mask of sanity. Of course, the whole 'at night' thing really does strike it as a good chance, but either way...

...Better safe than sorry. Would we be responsible for Mille's actions as Koax if she killed another innocent? Her being found out may encourage her.