If Archana had promised Shravani that she'll leave the house after baby shower then she should have left the house irrespective of what Manav wanted. It appears that the flip flop they are showing in PR all the time is because writer/s have no good reasoning or story planned. As a result all the characters behave like they have amnesia, like Savita forgets that she had sowed seed of jealousy for Archana in Shravani's conscience, Manav forgets that he is committed to Shravani and gets cosy with Archana from time to time, Shravani totally forgot what Manav told to Tarun about how he feels about Archana and thats why she blames Archana while letting Manav go scott free and then Archana promises Shravani that she'll stay only till baby shower and then takes hint from Manav's answers and agrees to stay.
Savita asks ' Do you wish to stay ' and she gave an honest answer that she wanted to stay after gauging Manav's answer too. The truth is she wanted to stay but had promised Shravani coz Shravani wanted her to leave the house. And then Savita makes her decision that Archana will stay and that was end of discussion. So for Archana, Manav's wish outweighs her promise to Shravani. She is ready to get humiliated in front of Shravani just to fulfil Manav's wish of having her stay in house for three more days. Archana had once made a mistake of not caring for Manav's wishes but she'll not make that mistake again.There was a time when Shravani used to smirk whenever Savita was mean to Archana, those smirk are difficult to come by these days. Everybody is driving her nuts. The scene where Savita tore the calendar was unnecessary. Shravani just had a baby shower and was happy about it and then Savita behaves like that? And Shravani takes out all of her frustration on one person.
Archana slapping Shravani was not at all in sync with Archana's character. Anyone could have slapped Shravani the way she was yelling but not Archana. OK so Archana will not tolerate two things –
1. Shravani bad mouthing Manav
2. Shravani talking ill about baby/Sachin's nishaani.
Still slapping Shravani was too dramatic. She could have yelled at Shravani instead.