Yun Lao felt his blood boil seeing his sister's actions, it was one thing to mock him, but physically assault him?
This was over the line!
He tried to squirm out from her foot pressing on his chest but his bones started cracking due to the pressure she put on it combined with his previous injuries not being healed.
He wanted to shout for her to stop as their father wouldn't want this to happen, after all, while he didn't explicitly said that they weren't allowed to kill each other his eyes told him that it was forbidden.
He just got that feeling of protection and love from him that he couldn't understand.
Yun Jhin was observing everything that was happening from above the planet, while he didn't want them to kill each other, hating each other was needed. For starters, they would be able to push each other to the maximum when it came to his love and attention, and secondly, they would never ally with each other thus splitting them into factions.