to be quite honest i dont blame the betiyans for their act, infact if truth be told, all of us in this forum wouldve reacted fierdcely like this.
your sweet elder sister gets married, instead of a loving husband, she gets a guy who beats, rapes and tries to kill her. Y we all forgetting during this period of time, saraswati is naive and innocent, being bought up in a male dominant family, she was always considered inferior, these kind of things causes trauma in the mind and heart which SOMETIMES CAN NOT BE REPAIRED.
sisters who saw their sister suffer, they wont stay quiet, why should they, together they always stayed, eat sleep and living their life. sharing eachothers pain.
they sent Bhavishya away to Mental Asylum, he is a cold hearted psychopath and instead of being chained or geting any councelling he gets out of there for revenge, this shows that he is mentally stable but he has no feelings,
he enters back to the family and this time for revenge, he is slowly killing one sister, the tries to harm his daughter and turnign the other mad, he plays multiple tricks on the family.
BOOM!!!!!!!!!!!! the sisters and mother loses there senses when they realised what happened here, do you seriously blame them, each and every duaghter has suffers, being a mother, with no family or husband support she bought her daughters up, you seriouly think she will let the perpetrator go away of course not, infact she would come after the life, same goes with saraswati, she also is a mother and bhav tried to kill her child, so naturally she will be vex. the sisters stadn united, they wont let go of bhavishya so easily.
they lured him into the temple, where bhav was screaming and laughing and saying in details what and how he has done injustice to them, you think they were enjoying listenign to that, am pretty sure, rage filled their heart but still they would not have killed if it wasnt for the fact that even though he was cornered and he could be put back in jail and all, he goes i will kill you and pushes Sav to the ground, what do you think, NO ONE and i mean no one can stadn it if anyone says anything to their mother and this guy pushes her and says i will kill you.
The sisters were clearly provoked for their act, being mentally stable does not mean you are sane all the time, there are times and places where someone actually loses their sanity because of the circumstances, they dont know what they are doing, the just do what that anger, frustration and hatred leads them to do, we might call it stupid, we might also call in disgusting but in true honesty in these kind of circumstances no one actully realises what they are doing. they kill, it is not self defense neither it is premediated killing, it is an act on the circumstance.