the son could still be alive, I think he likely is... but if the father really dies in the next episode, it would be very sad and bittersweet, ready to cry I guess
the hate towards the ending is very exgarrated, the children who whine about the male leads being dead would not be satisfied with original webtoon ending either, so... it was chilling and dark, bad ending would be her magically changing and living happily ever after with Jun Seo on country side
it's not open ending as in ready for season 2... and some of you call it bad ending because of who died? okay, that doesn't make sense as it really stayed true to the premise of her being sociopath and survivor but okay I guess, many of you are not mature enough to actually think about the ending...