This reminds me a bit of “Ringu“, an Asian horror film, in which also a girl is the absolutely opposite of innocence.
In addition, it’s quite notable that only affected people are shown, at the most, shadows of people who could help from the outside could be seen, except the health inspector. He is in essence a bridge to the outside world, which collapses, because he is also attacked at last. Pulling someone in, who’s first not involved in a bad situation, is a typical horror feature in several countries.
When Angela and Pablo flee to the top of the building and see pictures of and then the real possessed girl, the tension is at its highest and there’s “little time for questioning the narrative“ (Aldana Reyes 2016, p. 110) and so the movie becomes even more real. Aldana Reyes also writes, that “the lack of context for these monsters, in fact, adds to their creepiness“ (2016, p. 111) and he’s absolutely right, because we don’t know what’s wrong with them and don’t want to be infected,