Generally speaking, they abide by moral norms and are good people. In the crisis, they did immoral things for various reasons. Some people in the carriage are afraid of being infected and don't let the male host and his party enter. They kept pulling people to survive, and the aunt killed a car full of people out of revenge.
Aunt's own personality and temper are actually bad: mean (from her conversation with her sister, she hates her sister's rustic and cowardly personality in her opinion), willful (speaking without mercy, opening the door and dying with the people in the carriage), realistic (evaluating her sister's living conditions and pursuing material things more) and indifferent.
About indifference, there is a scene in the movie where the man in the main car opens the door and the aunt sits there, indifferent and acquiesces that everything has happened. Later, she went up just because she saw her sister. On the contrary, someone followed the aunt, someone wanted to rush up, someone held him and stopped him, which showed that at least the door in the carriage had made efforts. Therefore, the aunt is also a silent beneficiary. She didn't stop the closing party. Can she be regarded as a completely kind setting? She is an ordinary person with good and evil coexisting.
Aunt's behavior of opening the door is guilty, no matter what her own motives are or whether she has sympathy reasons, it is the same. Harm is harm. Doesn't mean killing bad guys is right. From the point of view of crime, no matter how many people they killed, once or continuously, the nature is the same-intentional homicide.
Besides motivation, most people agree that it is out of selfish "desperate for survival" idea, and they do not hesitate to pull people to do it. Aunt's motive is revenge, which seems to be selfish, but her behavior can't be considered unselfish. In fact, I have not formed a particularly mature idea about this. I didn't think clearly: why did she decide the life of the people in the carriage with a trial attitude? There is no difference? Besides, the standard of measurement is judged from her own point of view. ) Does she have this qualification?