My latest campaign has been moving along nicely, but as the PCs enter mid-level the paladin has gotten it in his mind that he is invincible. The group's rogue has an enemy from his past, a high level monk who's been looking for him for years. Recently the group gained some noteriety and this drew the monk to the area, the rogue spotted him first, but while he tried to slip out the back way the rest of the team went to talk to the monk.
Obviously a fight ensued. I had hoped that the group would flee when they realized what a powerhouse the monk was. At worst he would kill the rogue, take what was stolen from him and go. When the rest of the group started saying it was time to run, the paladin refused. He said there is no way that a single person, no matter how powerful, can beat 4 people, no matter how weak. When the team said they were going to go anyway, the paladin said he would stay and die. Of course no one felt right about going after that.
In the end the rogue convinced the paladin that he had an idea, so they ran, having maybe 20 hp between them. But the rest of the night the paladin player pouted, professing that because of the aura of courage this is how paladins are supposed to act (personally I think he's got a bad case of Sturm envy).
I want to prove the point that sometimes you have to run, and I know that killing off his PC will come off as hevey handed. Plus he'll be too busy throwing his usual you-killed-my-character tantrum to learn a lesson.
Any advice.