I think Sri and Tea love to joke or play around with each other as friend that why Siangwaan might be confuse on that...even the scene where Tea comfort Sri when she just have her argument with Paul, he joke with her that he going to "R" her...Even if Siangwaan saw that scene of Tae and Sri, um... what is he suppose to do, yell at Sri. A friend, will of course comfort her. I mean if he did that out of nowhere for example, the beginning, I would understand Siangwaan misunderstanding them. But the fact that she knew Sri was having a hard time, it shouldn't have come across her mind that Tae and Sri are more than just friends. She is just as bad as Tae when it comes to assumption and accusation.