Both of their team were pretending to be fighting. They had lazily played with their swords and rammed the swords to the swords of their respective partners, making a quite exaggerated fighting sound. Both parties were sitting down because they also felt tired due to the previous real fighting between them. They felt silly for doing this but they couldn't just ignore their masters' order.
If felt weird because they were enemies before... and now, they have to act together.
They didn't forget to make sounds of pain once in a while. They wanted to make the fight appear to be as realistic as possible in order to deceive the enemy.
"Arghh..."
"Ughhh..."
Or attacking sound...
"Hyattt..."
"Ciattt..."
They started to become creative due to feeling bored. Once they started getting out of hand, Lin Jian or Yu Wen would be reminding them to behave properly!