I was on at the time and you did not kill 4 players, I got slaughterd at least 3 times so I suggest you wait out your ban and face to consequences. A warn doesn't really come to Mass RDM'ers so they will normally ban you for a certain amount of time, if you only did 1 RDM for example it would execute in a warn.

There must always be a warn issued before banning someone. I looked in his f6, and he didnt got warned for Massrdm..