This author has written really wholesome MariAli, but I also remember another doujin where Alice was really torn, because she enjoyed Marisa's company, but she normally had a policy of collecting any human samples she could get for her research.
So if they say this doujin's Alice is bad news, she probably is. But then they also say this is a good ending from a MariAli perspective and that's the one I'm reading it from.
Anyway, I really like this kind of story where you never really find out how far the dark undertone goes. Yandere Alice is pretty common, but it's neat to see a version that would actually fool anybody.