hmm so does that mean...... SPOILERS INSIDE
So if they started of nice, and evil opposite comes out and kills nice person, what reflection does the evil one have now? Shouldn't it be a nice one as its opposite? But would the nice one kill?
shareMaybe being in the Other World makes you evil.
shareI don't know if they are evil, they are just trying to survive in this world, so they have to take the place of their this-world, mirror-image counterpart by killing them. Gina got a concussion and so became confused.
shareI think killing people in cruel manner instead of explaining the situation ("you're not going to believe this, but there's this mirror world, you see...") or even using less horrifying ways to kill makes them pretty evil.
Of course the mirror people could see the killing of their counterparts as "the necessary evil", since natural resources wouldn't last long with every human being and animal suddenly having a twin. Also they couldn't risk the word getting out about their arrival as that could result in them being hunted and killed.
Still, the way they kill people (violently and without emotion) definitely puts them in the "evil" category.