I'm starting from the part after they shake hands and she gets angry at him.
Bate- You're free now, your duties as a spy are done
Soh - What???
Bate- Your duties are done now. Just stay still until I catch Richard and his guys, and then you can go back to your life as a dara. Are we clear?
Soh- Hey you, isn't this too easy?? In the begininng when you wanted me to be a spy, you forced me so much, and now that I willingly work for you, you're just going to throw me away once I have no use anymore? Let me ask you, all your life, have you ever cared for anything?
Bate - Before you used to beg me to give you back your old life, well here, I'm giving you back your life. What more do you want from me???
Soh - You??!! You're going to return my life back to normal??!! You can't do that, because my life hasn't been normal since the moment I met you. There's no way it can go back to normal
Bate - Ok, Im sorry I turned your life upside down. Are you satisfied now? If you are go back to the house and go to sleep. Once I catch Richard, you and I are done. Finally, I can stop risking my life for you.
and this is when Soh slaps Bate
Bate - I'm not going to arrest you for assaulting an officer, lets say this is a bonus for you finishing your job as a spy ( You're such a douche Bate)
Soh - I know that you're worried for me, and don't want me to risk my life, so you're making me angry so that I don't follow you. But do you know what? I'm sad, I'm sad, I'm sad, do you understand? ( Soh is totally on to Bate, she knows he't just trying to protect her)
and cue the hug, look at the tears Peter and Margie are shedding
Bate - I'm so sorry Khun Dara, I won't do it again, but do you know something? It wasn't just your life that changed, my life changed as well, since the moment that I met you, and there is no way that it will ever go back to normal.
So thats it, it seems like they both confessed their feelings for one another, both of their lives have changed for the better, and I will be so sad to let them both go tomorrow night.
I know you love me phatman

It's like nearly 3:30 in the am, I'm going to bed now, goodnight. I hope we can watch it together tomorrow, you and I, I don't think I'll watch it live though, cause I have uni work to finish off and there are WAAAAAY too many ads on Thai tv during the lakorns. Goodnight.