I would have said something about kill order but nothing more than that, having to realize the price of DF is an occasional bad apple. If it was someone on my server, I'd make a note to never party with him again.

If anything, have the tank switch up marking if a dps refuses to listen. If the other dps is good they will adjust. Letting a dps die out of spite does nothing except start fights and slow down a dungeon run.