So possibly they just shot that promo earlier and she may not be wearing those clothes when she is kidnapped, but it's got me thinking that perhaps RK thinks she has run away from him.
Today Madhu said to RK, I can never come back to you as you broke my trust and my heart, then when he was defeated she gave him hope by saying "give me a hug a very tight hug and promise to always do as your heart tells you meaning what I trust is that you love me as much as I love you, but your head tells you to play games and hurt me, but your heart is good and won't lead you astray, go by that and we will be okay in our relationship" after they hug they were together even when they arrived home they were together having reunited.
In the morning, Madhu has disregarded that part and is resolved to stay away from him as he will hurt her, and leaves him, possibly thinks the drink was even spiked by him and not anyone else, as he engineers everything in her life to forward his own agenda, she probably thinks he planned to get her back to hurt her some more...After she's rescued by the new guy and is away from RK for some days she will come back to the set and avoid him, and new guy will be visiting her with messages from his child, RK observing all this and getting angry.