you can't go on implying some purpose without the author having stated it.
i dont even remember anymore but the only thing shown about it probably was that the backups deaths trigger a rewind without doing the first step. see, in either case its an alien death that triggers it - the backups or the servers. it does not mean they can trigger it willy nilly. not without an instance showing it happening in some loop
likewise, you can't go implying leaving the server alive (with broken antenna) and slaughtering everything else leads to a an inevitable rewind - be that as a result of "it feeling threatened" or it eventually dieing or whatever - even after many days and weeks later, without them trying it in some loop.
likewise, you can't go implying backups have infinite range and she couldn't just escape far enough away. not without an instance showing them trying and failing it. you also can't just go "the aliens could've hidden a backup at any time but they weren't smart enough for it". you can't just write the story however you think it'd make sense. the author had to do it and he failed at it.
you can play devil's advocate and make stuff up to explain all the plot holes to yourself, but unless the author wrote them they aren't an explanation.
Okay, but
WHY would killing a backup trigger a rewind if the antenna is up, vs it not triggering one when the antenna is down. Come on now, you're almost there, keep following the line of logic to the only possible conclusion.
If the server considers the battle to be lost or the obstacle facing it to have overcome it, it reverts and tries doing things differently. That is quite literally
the entire point of this bio machine, to support the terraforming. If there is an obstacle getting in the way of it terraforming, it rewinds and tries things differently, repeatedly, until it works. Does it not for one single second occur to you that it would be a massive oversight by the alien race that invented it, after having given it the ability to multiply, evolve, terraform an entire planet and even so far as fucking time travel, if it could be accidentally defeated by getting stuck after a rock falls over onto it which prevents it from moving, or something similar?
About the range thing, you've been saying over and over this entire time that the server definitely can't rewind on demand and only on death because it doesn't explicitly show it in the manga, yet you claim that Rita could simply walk out of range and that would magically work, despite at no point in the manga or book anywhere does it show that range is relevant at all. Why the massive inconsistency in your logic? By your own logic you should be saying range doesn't matter, because it never shows range mattering anywhere.
The problem is you refuse to question everything, use any basic logic at all or be consistent whatsoever, except when it's convenient for you. As soon as something comes up that would disprove your own faulty assumptions you desperately ignore it and refuse to think about it.
