Guys, I'm in a bit of a situation here

I was playing Pose with my friends, and two of them got into an argument. One of them suddenly left the game. Then, B (the one who started the argument, while A is the one who left) suddenly said 'Scaredy-cat' and started picking a fight. I told them not to escalate it, but they insisted on leaving a message on KakaoTalk. What should I do...? Since they're both my friends, I'm in a really awkward position in the middle...