When play fun escalates.

I have learned from listening to these calls that, 'my tolerances are too high'. I think this is an example of that but wanted your take on it.
I have pretty good kids (5 of them 7th grade to age 4), they do pretty well getting their chores and piano practice done each day without needing me to remind them. When it came time to gather for dinner my 11 year old son sat down, then my 12 year old daughter sat down, my son, being goofy, decided to get her arm wet using water from his cup. She got up and walked out. (I was in the kitchen and did not notice). My son proceeded to make goofy sounds, when my daughter sat back down she was annoyed with his noises and leaned forward to be loud and obnoxious with annoying sounds back in his face. (It was at that time I noticed something was going on, from my perspective my daughter wasn't being nice, I didn't know it was stemming from my sons previous getting her arm wet). I told my daughter to back off, hoping everyone would gather and we could get dinner started and move on. They continued to escalate but it was confusing to me because they kind of laugh like they're playing but then they're not doing nice things so I have a hard time knowing if they're 'having fun' or fighting. 11 year old boy pretended to pour water on his sister, but didn't. Sister decided to pour water on her brother, then he decided to pour water on her. Part of me was thinking, 'They need to see cause and effect', you get what you give, you give out negative, you receive it back. I was pointing it out to them as they were threatening each other with water. So, I hesitated to stop the situation.
I know my tolerances are too high. I'm curious how I should have approached this. What words should I have used?
When they came back into the kitchen I gave each of them a rag to wipe up their half of the kitchen. When my son protested I said, 'Just now I gave you an instruction and you ignored me, what you should have done was…' When my son hears me start he immediately gives in, interrupts me with some loud, 'Yah, yah I got it!' then does whatever I'm asking him to do and moves on. But we never actually finish the interaction. Maybe I should have him stand up and look him in the eye when I give him an instruction?
They cleaned up the mess and we ate dinner and moved on. But, I know I keep 'freezing in the moment' hoping they'll figure out their differences before I need to intervene.
Thanks for your time and genius mind Nicholeen.